Tuesday, December 29, 2015

Hooded Mergansers

A Hooded Merganser drake.

     Hooded Mergansers (Lophodytes cucullatus) are among the handsomest of diving ducks. They are also the smallest of our 3 mergansers (referred to as "Sawbills" and "Fish Ducks" by hunters due to the serrated edges of their bills used to catch fish and other creatures). Hoodies are about 18" and weigh less than 2 lbs. Indeed only the Eurasian Smew is a smaller merganser. The scientific name is derived from the Greek "lophos" for "crest" and "dutes" for "diver." Their specific name "cucullatus" comes from the Latin for "hood." Their distinctive crests or hoods are a signature field mark and also gives them other names that are sometimes used: Hairy Heads or Puffy Heads.


Some Hooded Mergansers, both drakes and hens, show why they are also called "Hairy Heads" or "Puffy Heads."

     Hoodies are also only indigenous to North America, rarely straying off the continent as they're relatives occasionally do. The term "merganser" comes to us by way of several languages. "Mergus" is Latin for "diver" while "anser" means "goose." Meanwhile "meer" is Germanic for "sea" and "ganser" refers to a "goose." All mergansers are are diving ducks, tend to be large, usually have crests, and have thin, serrated bills useful in catching prey. Hooded Mergansers are not only smaller, but frequent fresh water much more than any of their other native cousins. It is uncommon to see them in even brackish water as they favor fresh water almost exclusively.
     Although Hooded Mergansers are extremely good divers (their legs are set so far back on their bodies that they are clumsy on land) and are quite adept at catching fish, they also ingest more vegetable matter than other mergansers. In general, ducks that feed on vegetation are said to be much better tasting than ducks who feed on fish and other creatures. For a look at a juvenile both in and out of the water, check out this video:

               https://www.youtube.com/watch?v=v_5j6uJfCfg

     But while Hoodies are considered the least "fishy" tasting and best eating of the mergansers, they are rarely hunted. Indeed there is very little hunting for any type of merganser. I've had friends try and eat Hooded Mergansers and they tell me that they are quite horrid, no matter how you prepare them. So despite being legal to hunt during the regular duck seasons, no one really hunts them and there is very little hunting pressure for any other merganser either.
     Winter is the best time to see Hooded Mergansers in the DC area. Many overwinter with us, staying this far North as long as there is open water. They form small flocks of about 6-12 birds before pairing up by the end of winter. Drakes (males) do not attain their black and white "Hairy Heads" until the second year and do so only from Fall through the breeding season. First year birds look like females, with a disheveled-looking crest, except for having dark bills and yellow eyes. Adult breeding displays are neat to watch, with males showing off their crests, flipping their heads back as they try and convince hens (females), which are often in short supply, to pair up with them. 


A Hoodie hen.

     For a short video of them displaying, please check out this short YouTube video from the Capital Naturalist Channel:

               https://www.youtube.com/watch?v=wNXpfM_Spy8


Two Hoodie drakes displaying against each other with a hen nearby.

     Once they pair up, hens look for cavities to nest in (drakes take no part in rearing young as in most waterfowl), mostly North of our region, but a few hang around and attempt to nest. For quite a while, Hooded Merganser numbers had been low due to loss of habitat, particularly large enough trees with cavities for the hens to use. Some resort to nesting on top of stumps and as far away as half a mile from water. Shortage of suitable sites also results in their dumping their eggs into the nests of not only other Hoodies, but Wood Ducks and occasionally other waterfowl. Since they often are out competed by Wood Ducks for the same accommodations, it was a while before their numbers rebounded. 
     However, their numbers now appear secure. They likely benefited from nesting boxes put out for Wood Ducks and other conservation efforts. They also occasionally will share nesting cavities with Wood Ducks, laying their eggs among the Woodies' eggs and sometimes even taking turns brooding them. 


Hooded Mergansers with hoods both up and down.


     Typically in late March and April, hens lay 6-18 white, very round eggs, not preparing the nesting cavity with much more than the wood chips they find inside and some pulled feathers. After approximately 34 days of incubation, the precocial young are born. The next day, they jump from the tree cavity to the waiting hen below, much like Wood Ducks do and regardless of height. For more on Wood Ducks, their first jumps, and nest boxes, please refer to the Capital Naturalist Blog on Wood Ducks:        

     Hoodies can swim and dive right away after parachuting from their nest. This is helpful since so many predators are willing to eat them. The females lead the young around until they fledge about 70 days later. She will sometimes conduct a "broken wing act" to lure any potential predators away while the young dive and hide. This consists of her pretending that she is hurt and splashing around just ahead of the danger until she has led it away, before she miraculously recovers. 
     These handsome ducks are very good at taking flight off the water, not needing the long pattering along the surface that many other divers need. They seem very agile whether over, on or under water. Here's a look at a few on an Alexandria lake:

               https://www.youtube.com/watch?v=3hvgXLMYd8A

Every year I look forward to going to my favorite sites to watch them court one another, flipping their "hairy heads" back and chasing one another. They are not only among the prettiest of ducks, but also among the more interesting in the way they behave. 



Wednesday, December 23, 2015

Ring-necked Ducks


     Ring-necked Ducks (Aythya collaris) are among our most commonly seen and widespread diving ducks. Their name is not a very good one however. The males certainly do have a cinnamon or chestnut colored ring around their necks, but this is faint and a terrible field mark. It is really only evident in good light, at close range, and on an adult male in full breeding plumage. It was given to them from dead specimens that were held in the hand and so is not very recognizable in the field. They were originally described in 1809.
     A much more appropriate common name is used by others, specially hunters. They are often called Ringbills or Ring-billed Ducks, since the ring is much more noticeable on the bills of both adult males and females. Other common names that hunters use for them include Blackjacks and/or just Jacks due to their dark coloration.

A Ringbill showing both the crescent mark and ring around the bill that are the best field marks.

     But the best field mark, on the drakes (males) at least, is a white bar or crescent-shaped mark along the side that is often visible even from a distance. These medium sized (17" and between 1-2 lbs, drakes being larger) ducks have an overall dark appearance, the backs on drakes being black rather than the grey of their cousins the scaups. They also have a peaked or pointy looking head that has a purplish sheen on males in good light. Adult drakes also have yellow eyes. All in all a handsome duck.

A Blackjack drake

     Although they are diving ducks, these are a bit different from most other divers. For instance, most diving ducks (unlike dabbling or puddle ducks) need to run or patter along the water's surface before being able to take off. Ringbills are very strong fliers and can take off directly from the water with out much or any running necessary.
     Ring-necked Ducks also feed on much more vegetable matter than most other diving ducks (Redheads and Canvasback Ducks being notable exceptions). Three-quarters of their food is plant material throughout most of the year (though while nesting they need much more animal protein, as do the ducklings). Due to this mostly vegetarian diet, Ringnecks are considered to be mild tasting rather than "fishy" like other divers, and are thus favored table fare over them. They respond to hunters' calls and decoys (even those of other duck species) quite well which also makes them popular game birds.
     Ring-billed Ducks appear to be less wary than other diving ducks. Other divers gather in huge rafts, but are often in very deep water and so far in the distance that you cannot get very good views of them, even using binoculars or spotting scopes. You can often get much closer to Ring-necked Ducks before they either fly off or dive under.

A pair of Ringbills, hen to the left.

     Another difference between them and many other divers is that Ringbills prefer much shallower water, often 4' or less, where most of their plant food grows. This means they can utilize some food sources and habitats that many other diving ducks cannot. This includes beaver ponds, flooded fields, storm water control lakes, reservoirs, and just about any fresh body of water (they may use brackish water bays, but tend to stay away from salt water). Blackjacks also can eat a great variety of water plants, whether from flooded fields or even invasive hydrilla.
     This also means you can also find them just about anywhere and makes them much more common in our region than many other diving ducks such as scaup, redheads, or canvasbacks. Ringnecks tend to be in small flocks of half a dozen or so birds around here, but can congregate in the thousands in some of other areas. They also tend to be quite content mixing with rafts of other ducks, whether other divers (especially scaup) or dabbling ducks.
     Ring-necks can dive 40' or so feet underwater in pursuit of food, but usually make much shorter trips. In fact, they will sometimes just feed on the surface or tip-up much in the manner of dabbling ducks instead of the divers they are.
     Ringbills are powerful fliers. Their small flocks can fly day or night (indeed you can sometimes hear their whistling wings and recognize them for Blackjacks without even having to see them if they're near by and spooked). Blackjacks can travel very long distances, some straying all the way South to Venezuela and across the ocean into Europe. They are only with us during the winter, returning to their breeding grounds in March or April most years.
     Ring-necked Ducks breed mostly in Canada, although they also nest near the Great Lakes and have spread their range into the Northeast. They tend to choose ponds with lots of vegetation and may use the same ponds (and even the same nest) year after year. Older hens lay larger clutches and are more successful than younger ones (although some nest after the first year, many wait until after the second). Females may also dump their eggs into other Ringbill or even scaup nests.

A pair of Ring-necked Ducks, hen to the right.

     Hens nest in very precarious locations. This sometimes consists of just bending some vegetation over and laying the first egg on top of them right on the water. It may only be a couple of inches above the water level on a floating platform. She adds material as she lays a single egg each day until she has her complete compliment of 8-14 olive eggs and the nest is completed.
     Drakes are unusual in that they sometimes stay with the hen even as she's incubating her eggs (though like all ducks, he does not help with raising them). After about 27 days, the precocial young hatch. The next day, they follow the hen, but again differing from other diving ducks, may not look for open water but stay feeding in the aquatic plants near the edges. Ring-necks may creche their young, 1-3 females combining their broods. They can be bullied by larger birds, with Loons and Grebes having been documented as attacking them.
     After about 50 days, the young are fledged and can fly. Though diving ducks may abandon their young before they can fully fly, Ringbills tend to stay with them until they can fly successfully. If they're lucky, they may make it to the record life span of 20 years and 5 months that one banded bird made it to. The toughest task may not just be survival, but finding a mate if they're male. Of all our ducks, none has a more disproportionate male to female ratio than Ringbills. Seventy percent of them are drakes.

A raft of Ringnecks. Can you find the lone female? 

     Ring-necked Ducks, perhaps because of they're adaptability in both habitat and diet, are doing quite well. In fact, they've actually spread their range. Before the 1930's, they were considered rare in the Northeast. By the 1960's they were common. By the 1980's they spread into Alaska. They number now a steady 1.2 million or so and are our most common and widespread diving duck.
    These handsome waterfowl may be widespread and common, but I look forward to seeing them every fall and winter. I like being surprised when encounter them in unusual places and that I can often get better looks at them than I can most other diving ducks. I'm also happy that they've adapted and even spread due to their adaptability, even in our changing world.
               Here's a short video from the Capital Naturalist YouTube Channel showing them on the water: https://www.youtube.com/watch?v=XLyAuzHGusA



Monday, December 21, 2015

Christmas Fern


     Christmas Fern (Polystichum acrostichoides) is a perennial evergreen fern that grows throughout our region. Because its fronds are evergreen and long-lasting, it was a popular Christmas time decoration, and thus the name. Each individual "leaflet" (pinna) looks a bit like a Christmas stocking as well, something that helps to identify and name the fern. Its Genus name comes from the Greek for "many" and "rows" and refers to the large amounts of fruiting dots (called sori) that release spores on the undersides of the leaves.

A Christmas Fern bootie: a leaflet (called a "pinna" in ferns) in the shape of a Christmas stocking.

     This is a very adaptable fern. It can take a variety of growing conditions, though it prefers rich, loamy soil and light shade. Because of its adaptability and evergreen nature, it is a popular garden fern. The root stock (rhizome) is easily divided in the spring and fall to get new plants. Christmas ferns are mostly pest free, though an introduced European aphid, Amphophora ampulatta, sometimes attacks it and other ferns. Even deer tend to leave it alone unless very hungry.
     But there certainly are animals that use it. At least 3 native species of caterpillars feed on it for example. Actually, I had some interesting discussions a couple of years back when several people asked me to identify an insect that was folding and tying together Christmas fern fronds. At first I thought they were a kind of Crambid moth called a Serpentine Webworm (Herpetogramma aeglealis) which is a leaf tier that feeds on ferns and occasionally a couple of other plants.

A couple of bundled up Christmas fern fronds, possibly the work of the newly discovered leaf-tier moth Herpetogramma sphingealis. 

     But then I started finding them in several parks, including in some gardens that had several other fern species, such as Cinnamon and Sensitive ferns which are supposed to be preferred host plants for the caterpillar. What was strange was that all the tied-up fern fronds were exclusively on Christmas fern and not on any of the other ferns.
     So I did some more research and found out that some folks were investigating a potential new moth species discovery in both Canada and Maryland that exclusively used Christmas ferns. The new moth was officially recognized and named in 2011 as Herpetogramma sphingealis (no common name). This moth is both darker and larger than the Serpentine Webworm. I started seeing the bundled up leaves on Christmas ferns in numerous parks all over the DC area, including in Arlington. I'm now convinced that this is that same species, but will have to rear some this summer to confirm (and send it off to some Lepidopterist-expert friends since the only absolute identification is by dissecting genitalia under a scope). It's quite neat to know that people are still discovering new species, even in very developed areas.

Christmas fern fiddleheads unfurling.

     But back to the Christmas fern itself. It's been used by Native American Indians quite extensively. Although many fern fiddleheads (what freshly unfurling fern fronds are called) are edible, apparently only the Cherokee utilized Christmas ferns in this way. The Cherokee also used the roots to treat rheumatism (especially of the hands). A drink was concocted from it to treat fevers, tooth aches, pneumonia, and stomach illnesses as well.
     The Haudenosaunee (Iroquois) also made great use of it, particularly to treat their children. Concoctions were used for children's cramps, rheumatism, diarrhea, sore backs, spinal troubles, convulsions, body discolorations, and general listlessness. It has been documented (all these by expert ethnobotanist Daniel Moerman) as being used in adults for speech impediments, tuberculosis, venereal diseases, as a blood purifier, and as a "lady's medicine." The Micmacs and Malecites chewed the roots to treat throat hoarseness.
    So this plant has lot of history to it, though now it's mostly remembered for its holiday decor.

A Christmas Fern colony

Thursday, December 17, 2015

Northern Shoveler

A Northern Shoveler drake.

     The Northern Shoveler (Anas clypeata) is a very distinctive, medium sized (19" and about a pound and a half) duck. Although the drakes (males) are very colorful, it's their spatulate-shaped beak which stands out the most. It gives the Northern Shoveler (or Shoveller in British English) a variety of its common names used by hunters or regionally: Spoonbill, Shovelbill, Shovelnose, Broadbill, Spoonie, Bootlips, Smilin' Mallard, Broad-faced Mallard, and Neighbor's Mallard (the last three due to the green-headed resemblance to the common mallard). Some even believe it (along with the three other Shoveler species worldwide) deserve their own genus, Spatula, based on the beak shape. It's specific name clypeata also means "shield" due to the shape of the beak.
     The spoon-shaped beak is specialized to help the duck strain out food. It is not only very broad, but has about 110 projections, comb-like "teeth" called lamellae that they use to strain their food. Spoonbills use these to filter out all sorts of food, but in particular small macro-invertebrates and plankton. Of all our dabbling ducks, they ingest the most animal matter. About a third of their diet consists of small aquatic organisms.
     Dabblers, or puddle ducks, are what most people envision when they think of a duck. They take off directly from the water, do not regularly dive underwater for food, and eat mostly plant material. Diving ducks on the other hand dive under water to catch their food, which consists of much more animal matter, and need to run across the water's surface before they can fly. Shovelers however eat a larger proportion of animal material than other puddle ducks. They rarely, they can dive, and do not generally tip bottom-up like other dabblers to reach their food.
     Spoonies tend to just dabble and skim their big bills along the surface, catching whatever food they can. They sometimes seem to cooperate in getting their food, occasionally pin-wheeling among each other and catching what they kick-up for each other. At other times they just line up and cover a wide area. They may also follow other water birds, filtering what ever they churn up. Shovelers prefer freshwater in the warmer months, but will utilize brackish bays and estuaries while wintering. They are also not as picky about where they feed as far as water quality, sometimes utilizing stagnant or polluted pools that other waterfowl avoid. Here's a short video showing a Northern Shoveler drake dabbling:
         https://www.youtube.com/watch?v=7zb8A6K9u7Y

     Because a higher proportion of their food is animal matter, these ducks are not considered good eating like other ducks who eat more plant material. It is believed that such a diet taints the flavor of the duck. Their dark meat is not favored by hunters, though they can be decoyed easily, and so they are not heavily hunted.
     Spoonbills breed well up North in late spring, but they pair up while wintering in the South. They nest in Canada, the Great Lakes region, and in Northern pothole country. The drake (male) stays paired with the hen much longer than most other ducks, though he (like all other ducks) does not assist in raising the young. He will accompany her well into the incubation period, long after other male ducks have abandoned their own mates.

A pair of Spoonbills, hen to the right.

     Shovelers will nest farther from water than most other ducks, over 100 yards away at times, but they prefer to nest closer when they can. The hen lays 6-14 pale greenish eggs in a shallow depression on the ground, often near the place she nested the year before. If she is flushed off the nest, she will sometimes defecate on the eggs before leaving, perhaps in an attempt to protect them. If the nest is destroyed, she will often re-nest like many other ducks also do, but the second nest will have fewer eggs. After 24 or so days of incubation, the precocial young are born. In under two months, they are fledged and can fly.
     Northern Shovelers are strong fliers. Though they may appear a bit ungainly due to the over-sized bills, they are also very agile. Their tight-knit, small flocks (5-10 birds is the norm) fly erratically, swerving, diving and circling. During migration, they regularly end up in Central America, with some having been found in Trinidad and as far South as Colombia. Some fly from Alaska to Hawaii as part of their normal migration as well.
     Though not common locally, Northern Shovelers are very common and widespread ducks. They are more usual in the West and Central parts of the USA. They also range into Eurasia. Due to their strong flying ability, Spoonies have been found on every continent except Antarctica. The European ones regularly stray into Africa and some vagrant Asian ones have even ended up in Australia.
     Northern Shoveler populations have been very healthy since the 1960's. In fact, they are considered the second most common ducks in North America. The US Fish and Wildlife Service estimated their population at 4.6 million strong in 2009. Regardless, since they're not as common locally and stand out due to their appearance, I enjoy whenever I find them. Here's a short video from the Capital Naturalist YouTube Channel to wrap up:
          https://www.youtube.com/watch?v=jMGJ3iUs7aE

Wednesday, December 16, 2015

Green-winged Teal

A Green-winged Teal drake.

     Everything is diminutive when it comes to Green-winged Teal (Anas crecca). They are the smallest dabbling ducks in the Americas. Dabblers, or puddle ducks, are the typical ducks who tip their bottoms up to reach food below the water's surface and who can take off directly up into the air. Contrast that with diving ducks who dive under to get their food (which includes more animal matter than dabblers usually do) and who need to run along the water surface to take off. Green-wings average about 14" and weigh less than a pound.

A Greenwing tipping up to reach for vegetation.

     Now all teal duck species are all small to begin with. In fact, "teal" comes from a medieval English word "tele" which actually means "small." But Green-winged Teal are the smallest of the batch. Indeed, hunters sometimes refer to them as a "Pound of Butter" as they weigh about a pound.

A handsome Green-winged Teal drake (male) dwarfed in size when compared to a Canada Goose.

     Green-winged Teal are very handsome birds though. The drakes (males) are considered by some to be close rivals to Wood Ducks in their beauty. In good light, the colors really come out, including their rusty heads and mask they have around their eyes. One of the best identification features though is the white bar that comes up along where their shoulder and wing would be. This also helps to distinguish them from the Eurasian Teal that is an occasionally vagrant or accidental from overseas, getting blown over and which lacks the white bar. The green speculum or patch on their wing though that give them their names is often difficult to see and does not make a reliable field mark.
     Green-winged Teal diets are 90% vegetable matter. This consists especially of small seeds such as those of smartweeds, sedges, and rushes. They will also eat corn and grains among other things however. Though they are dabblers, they also are the ducks most likely to feed on mud flats.

A Green-winged hen (female) feeding on the surface behind a drake.

     These small ducks breed well up North, in the boreal, tundra and prairie pothole regions. They migrate South early though and can stick around with us for a good part of the winter if it stays warm and the water remains unfrozen. Most however concentrate their numbers in Louisiana and Texas. Some even make it all the way down to Colombia.
   When nesting, Green-winged Teal have fairly large egg clutches, averaging 7-15 olive eggs at a time. They can nest quite a distance from water at times, up to a mile on occasion. Their eggs hatch quickly in under 3 weeks. They are also the fastest growers of our ducks, reaching maturity in less than 40 days and are ready to breed in one year.
     These means that they can be found in large numbers, forming huge flocks at times (outside the breeding season) of over a hundred birds at a time. The US Fish and Wildlife Service estimated their population at 3.4 million in 2009. Greenwing flocks are very compact and fly very quickly. They often circle and false-land repeatedly, reminiscent of a flock of pigeons, if you've ever seen them over cut corn fields. They twist and turn in amazing coordination, not bumping into one another despite their tightly packed ranks. When they finally do decide to land, they all seem to want to do it at the same time it seems.
     I once observed a large flock of 50 or more Green-winged teal that circled the blind I was occupying on an extremely cold winter day just as the sun came out. After repeated circling, they all tried to land on what they thought was open shallow water right in front of me. Instead it was frozen solid. It was amusing to watch the little ducks slip, skid, slide, tumble and crash on top of the ice all at once. They quickly recovered though and flew up into the air in unison, no worse for wear.
     These little ducks may be small, but what they lack in size they make up for in character and appearance. It's always a joy to see them on the marsh. Here are a couple of videos from the Capital Naturalist YouTube Channel that shows them feeding (including dabbling) and among some larger cousins:
          https://www.youtube.com/watch?v=TY3mL-rQs6g

          https://www.youtube.com/watch?v=-qiaRvhdBjM



Tuesday, December 15, 2015

Gadwall

A Gadwall drake preening itself.

     The Gadwall (Anas strepera) is an often overlooked duck. The drakes (males) have an understated elegance about them. Not gaudy like some other drakes, they still have some fine features, especially when seen close up. From a distance though, they appear like a grey duck with a black butt. This gives them their other common name of "Gray Ducks." Though never abundant, they are very widespread, living in Europe and Asia as well as most of North America.
     The males not only have a black butt, but a black beak as well. In profile they have a very angular head, giving them one of their other common names: Square-heads, though this is mostly a name given them by hunters, along with just calling them "Gaddies." No one is sure of the origin of the name Gadwall, but some think it's from the Anglo-Saxon "gad" meaning "point" maybe having to do with the fine "teeth" they have along their bills.

This Gaddy hen shows the typical white speculum wing patch, but this is often hidden. 

     Many identification books tell you to look for the white "speculum" or white feather patch near the end of their wings, but frankly, that's not always easy to see, except maybe in flight where it's conspicuous. Better to look for that overall grey duck with the black butt to ID a male Gaddy. The female is easily confused with other hens when the white speculum isn't visible however.
     These birds are usually in pairs or very small flocks, often mixed with other "puddle" or "dabbling" ducks such as Mallards and Pintails. They also like to stick to open, shallow and fresh water. Typical of the puddle ducks, they usually feed on or near the surface, tipping up to reach food below when necessary. Unlike many other "dabblers " though, they can also dive to reach food beyond their reach. They are also known for stealing food from coots or diving ducks when they surface. Gadwalls prefer to eat seeds and other vegetation. Plants makes up 98% of their diet. Like other puddle ducks, they can take off straight into the air without needing to run along the surface like diving ducks need to do.

A Gadwall pair, hen to the left, with the white speculum that's not visible on the male in this photo. Note his black bill.

      As widespread as these ducks are, they actually were not common in the East. Before the 1950's it was considered rare to see one. But in the 1920's, hunters from Long Island introduced them from the West and their numbers have been steadily increasing since then. Now it is not surprising to see them, though again, they're never common.
     Gaddies prefer to nest on islands when they can. They hide their ground nests in long grass, laying 7-13 white eggs in them. They are late nesters, arriving late onto their breeding grounds, which are mostly North of here and concentrated in the Northern prairie states as well. They have a short incubation period for a duck, with the eggs hatching in under 4 weeks. The precocial young can fly less than 2 months later. Gadwalls are prone to nest parasitism. Not only will they lay their eggs in each others nests, but Scaup ducks often lay their eggs in Gaddy nests too.
     These are quiet ducks for the most part, not standing out in a crowd and liking to fly at night. But I enjoy spotting them, perhaps because they are not that common and are not show-offs.

Monday, December 14, 2015

Wood Ducks


A Wood Duck drake

     Wood Ducks (Aix sponsa) are arguably the most beautiful ducks in North America. They have a variety of common names that are sometimes used for them. The colonists used to call them Summer Ducks, while regionally they are sometimes still referred to as Carolina Ducks, Swamp Ducks, Acorn Ducks, or just called Woodies. Their scientific name "Aix" comes the Greek for "waterfowl" while "sponsa" refers to "betrothed" or "beautiful bride" in Latin due to the beauty of the species. It is the only member of this Genus in North America (the only other Aix is the Mandarin Duck of Asia, Aix galericulata). Being a true all-American and handsome duck, it should surprise no one that it once was a candidate for our national symbol.

A pair of Wood Ducks, hen in front.

     Wood Ducks are now one of the most common ducks throughout North America, perhaps the third most common on the Eastern coast. But that was not always the case. By the early 1900's, Woodies were in serious danger of extinction due to market hunting for their meat and fine feathers (a staple on ladies' hats and fly tying), as well as destruction of wooded swamp habitats and especially the old trees with cavities needed for nesting.

Wood Duck feathers were popular for such things as ladies' hats and fly tying.

     By 1918 however, the Migratory Bird Act was passed and all waterfowl received protection. Thanks to the advent of nest boxes that conservation and hunting groups put up for them to nest in, Wood Ducks have made a remarkable recovery. This was probably helped along with the resurgence of beavers with the wooded ponds they construct and which these ducks prefer. They still benefit of course from such fees as hunting licenses (including the mandatory Migratory Bird Stamps and such needed prior to hunting) and the tax on all hunting related equipment such as lead-free ammo. Their greatest threat now, as for any waterfowl, is the need for wetland habitats.
     As mentioned, these are cavity nesting ducks. They normally use dead trees (snags) with large cavities in them. But they readily use man-made nest boxes as well. The female usually chooses the nest site (which may be used over and over again if they're successful) and she does little more than pluck a few feathers to place inside the hole. Hens lays 7-15 eggs which are incubated for about a month. Wood Ducks are the only ducks in North America that commonly nest twice in a single season.

A Wood Duck nest box. This one has predator guards to help prevent animals such as raccoons  from raiding them.

     Wood Ducks are well known for egg dumping. This is when a hen lays her eggs into another wood duck's nest. This seems to occur more with inexperienced first year birds, but can also happen when there are not enough nest sites available. Interestingly, it can also happen when nest boxes are too close to each other as well, regardless of how many nesting cavities or boxes are available. Normally nests containing more than 15 eggs are assumed to be dump nests. These have a much less chance of successful incubation and up to 30 eggs can be dumped in one single nest.
     Once the precocious young are born, they all remain inside the nest-hole for about a day. After that, they all climb up from inside the tree trunk or box using their claws and hooked beak-tips (features few other ducks have) and simply jump out. Their mom only helps by calling for them from below. They can fall upwards of 30' although 8'-10' is more typical. The young cannot fly of course, but seem to just bounce off the ground or into the water, little worse for wear regardless of the height fallen.
     Twice I've been lucky enough to catch this remarkable event, which rarely lasts more than 5 minutes once the first chick free falls. Once when I was fishing along the Shenandoah as a teen, I heard a Wood Duck hen calling. When I turned to look, I just caught the last two chicks plummeting into the river and being led away. It truly was a wonderful experience.

A Wood Duck hen leads her chicks at dusk.

     The second time was a bit stranger. I actually was at the National Zoo when a group of people in addition to myself saw several little ducklings emerge from a nesting box they had in one of their open air pens. However, the second to the last chick actually got its foot caught (maybe because of its long hooked claws?) in some screen that was on a little ramp by the nesting box leading into the water. The little guy looked to be in trouble and was half submerged, though its head was above the water. After realizing it was stuck, I hopped the fence and quickly tried to free it. Frankly, it was practically free already by the time I got there. Unfortunately for me, that was the exact moment a zoo keeper walked by. He was a bit upset that I was in the pen... Thankfully the rest of the people that were there explained my good intentions and the zoo keeper was nice enough to not cause me any trouble.

     Here's a short video of some woodie ducklings following their mother:     
               https://www.youtube.com/watch?edit=vd&v=Hdon8XeXMfs

These are juvenile Woodies, haven't quite gotten all their beautiful plumage yet.

     Woodies eat a variety of different foods, but are for the most part herbivores. As their name of Acorn Duck implies, they heavily favor acorns and other nuts, swallowing them whole. But they eat a great variety of other seeds too. I've witnessed flocks of 30 or so dropping into cut cornfields at dusk to glean spilled corn for example. Woodies seem to like duck weed as well. When young in particular, they will feed on insects and other invertebrates. Some stomach sample studies reveal what appears to be quite a preference for spiders as well. They seem to dislike shellfish and mollusks though. Wood Ducks themselves are considered good eating, some think due to their herbivore diet.
     Here's a short video of a pair on a duckweed-covered pond from the Capital Naturalist YouTube Channel:
                        https://www.youtube.com/watch?v=FlbXGtZOJgo

     Wood Ducks are fairly swift and agile fliers. Some have timed them flying up to 47 miles per hour. I've always marveled at their agility when flying through flooded timber, even in very dark conditions. Their eyes (which are a striking red on the drakes (males)) are proportionally the largest of any of our ducks in size, perhaps helping them see in dim light. They are also quite fast on their feet. I've seen males chasing females, especially around March in our region, on merry foot-chases through the woods, sometimes oblivious to my presence in their ardor to get the female.
     The vast majority of Wood Ducks are gone for now, most migrating out of the DC area by November or so (thus the name "Summer Ducks"), but they'll be back soon enough. I look forward to seeing them once again flying through flooded woods, the drakes giving their whistles, while the hens their distinctive "Oooo-eeek" calls... one of my favorite sounds at dawn and dusk...



Wednesday, December 9, 2015

Marcescence and the Legend of the Evergreens

An American Beech tree holding onto its leaves through most of the winter

     While many people know the difference between deciduous trees who lose their leaves during a short time in the Fall, and the evergreen plants who stay green all winter long, few have heard about marecensce. To be honest, while I knew about the phenomenon of how certain species of trees held onto their dead leaves well into winter, I did not know it had a term until just last week. I was attending the graduation of a master naturalist class and marecensce was the topic of one graduates' presentation. That's one of the neat things about being a naturalist, you learn something new all the time.

An Ironwood (Musclewood) with dried marcescent leaves hanging on into winter

     Leaves are shed because deciduous trees are trying to conserve water that may be hard to get once it freezes during winter. Since the shorter days of winter are not conducive for effective photosynthesis anyways, the leaves are no longer needed. So the chlorophyll is no longer produced and we get to see the hidden Fall colors that often had been masked by the green chlorophyll.  An abscission layer, sometimes called a separation zone, is formed between the tree's petiole and leaf that effectively cuts off the leaf and allows it to fall off.

A Pin Oak has had the top part of its leaves blown off but retains the lower ones.

     But some trees, in particular the oaks, beech, hornbeams, and musclewood trees, do not form this layer and the leaves do not just fall off. In fact, some may be retained well into the winter or into early spring, where new growing leaves can finally cause them to drop. Strong winds might still blow off the dead leaves, particular those at the top of the tree first, but otherwise they stay connected. Some also suspect that smaller trees and lower branches may have more marecescent leaves to allow them to get sunlight for a while longer since the higher leaves have fallen off first. Marcescense  is the term given to the retention of dead plant material that is normally shed in other trees.

Ironwood (Musclewood) leaves in winter still hanging onto the branch.

     Why some trees retain their dead leaves and others don't is not completely understood. Some theorize that it may help with predation so hungry herbivores (such as deer) chew on the hanging dead leaves while hopefully leaving the buds and twigs alone, but no one is really sure. Regardless, it is easy to notice these trees these days prior to the strong winds of winter. While I say no one is sure as to why this retention of leaves may have evolved, there is a legend told by the Seneca people, the westernmost nation of the Haudenosanee people (whom some people call the Iroquois) which explains why this came to be.
     I've told this tale many times, though I take some liberties to replace some of the trees they mention that are found in their New York home with some more appropriate to our area. So I substitute the Tamarack (Larch) tree they have with Bald Cypress for example. My version of the story goes like this:
     A long time ago, the continuous struggles of the spirits of winter versus the spirits of summer were taking place and certain beings were choosing sides. While many of the trees tried to stay neutral and just submitted their colors and leaves until the summer spirits won out, a few were determined to show resistance and decided to back the summer spirits. The Conifer Tribe was among these and decided to hold a meeting to decide how to best show their support and resistance.
     So all the members of the tribe gathered, with White Pine taking the lead and telling them of a magic elixir it had brewed that would allow them to stay green all winter long and thus declare their support for the spirits of summer. The American Beech heard about this and asked to take part in the protest. But Bald Cypress took offense at this. He pointed out that Beech was not a member of his Conifer Tribe and should not be allowed to participate.
     While White Pine acknowledged that this was the case, he insisted that the pines and other conifers needed allies, and that if the oaks, beeches, and musclewoods wanted to show their support, they should be allowed to do so. This so upset Bald Cypress that it stormed out of the council, refusing to take part in any more of the activities of the tribe.
     When time came to give each tribal member a dose of the magical evergreen elixir, the Conifers decided to hold one dose for Bald Cypress in case he returned, but he never did. As it was, there was not enough to share with the beeches, oaks, hornbeams, and musclewoods, so they did not get any.  
     When the spirits of winter saw this show of resistance and protest, they howled and caused it to be the coldest, snowiest season in memory. The bitter winds blew and the harsh cold attacked the trees with fury. Most of the trees lost their leaves and remain deciduous to this day.
     The Conifers though, along with a few other rebels, managed to stay green. All of them around here that is except for Bald Cypress. Having not drank of the magical elixir, it remains one of the few members of the Conifer tribe to lose its leaves. The beeches, oaks, and musclewoods did not have the benefit of the magical potion. They were battered by the wind and cold, some eventually losing their leaves, but most hung on.
     They knew if they held on long enough, the spirits of summer would eventually prevail. So they may lose their colors, lose limbs and some leaves, but they continue to rebel. So it is to this day that these trees retain their leaves, challenging the cold and wind, holding onto to the end of winter when they can. It is said that when the wind blows and tries to knock off the leaves, those who know the tale and remember the past know what is really happening and can hear what others do not. For if you listen to the rustling leaves hard enough, you can hear that what they're actually doing is laughing at the spirits of winter, secure in the knowledge that summer will one day again prevail, with the support of the allies among the trees...


Wednesday, November 25, 2015

Eastern Chipmunk



     The Eastern Chipmunk (Tamias striatus striatus) is the familiar striped ground squirrel we encounter on many of our woodland walks. Since they will soon become less common, going into torpor and sleeping for large parts of the winter, I thought I'd write about them now. They are not true hibernators, waking every few weeks to feed on warmer winter days, but most are hidden in their underground burrows by December.
     As mentioned earlier, these are ground squirrels, the only members of the subgenus Tamias and having 2 fewer teeth than other chipmunk species. Almost all chipmunk species are found in North America, the only exception I'm aware of being the Siberian Chipmunk. The sole local representative we have is the Eastern Chipmunk. Being squirrels, they all can climb, though they prefer to stay on or under the ground. I've seen as many as 4 at the same time up in a single Bird Cherry tree picking fruits however. The photo below shows one in the low branches of a shrub.

An Eastern Chipmunk stares at me from its tree perch.

     These are small rodents, usually under 10 inches including the tail, and weighing under 5 ounces. Eastern Chipmunks are strictly diurnal and are extremely active during their waking hours. They are also quite vocal, chipping, chirping and otherwise sounding off in the woods. Some think they're called chipmunks because of the chipping sounds they make, but it is more likely that their common name is derived from either Ottawa or Ojibwe words that were corrupted to "chipmunk." Their Native American Indian name is supposed to mean "one who descends trees headfirst."
     Their stripes are a distinguishing feature and there are several legends concerning how they got them. My favorite is a Haudenosaunee (Iroquois) tale relating how the chipmunk, never lacking for something to say, challenged a cocky black bear. The bear was proud and thought there was nothing he could not do, so the chipmunk challenged him to keep the sun from rising. When the bear failed to do so, the chipmunk loudly chattered with mirth and told all the other animals of its failure. The bear was so angered that it pinned the chipmunk under its paw, proclaiming that though perhaps it couldn't stop the sun, it could keep the chipmunk from ever seeing another sunrise. The chipmunk begged for a chance to say a last prayer, if only it could get a bit of breath to do so. When the bear raised its paw ever so slightly, the chipmunk ran for its burrow. The bear was quick enough for one last swipe with its claws, leaving 3 striped scars forever on the chipmunk's back.
     Because Eastern Chipmunks are not true hibernators, they need to collect much food to have ready over the winter. They cache large stores of nuts, seeds, and bulbs for their regular forays to get food. They keep several stores at the ready, just in case another animal finds their hoard and steals it.
     These underground stores require a great deal of food collecting. They do this by carrying the seeds and nuts they find in cheek pouches back to their larders. They can expand their cheeks up to three times the size of their heads, filling them one cheek at a time. They can carry 5 peanuts at a time. The famous naturalist John Burroughs studied one individual chipmunk over three days and said it carried off "...5 quarts of hickory nuts, 2 quarts of chestnuts, and a quantity of shelled corn." That's right, in THREE days. For a short video of one collecting seeds and nesting material, please check out this video from the Capital Naturalist YouTube Channel:
https://www.youtube.com/watch?v=Gv9vFidSZlU

     Because they are storing the seeds and nuts all in single locations and destroying the seeds as they need them, they are not very good at dispersing seed. They do however also eat a fair amount of mushrooms and fungi and are thought to disperse those spores quite a bit. Chipmunks also occasionally eat insects and raid birds nests, but not that often.
     Chipmunks are very vociferous. They make a variety of calls in addition to the alarm call we often hear when one spots us and takes off running for its burrow. One such call is only given for a very short period of time (maybe a day) when the female is in estrus. For a short video of one giving this call, check out the following:
https://www.youtube.com/watch?v=Lm5MmdA6_WQ

     Female chippies mate with multiple males before giving birth to up to 8 (but 3-5 is much more common) young. Gestation is about 35 days and it takes about 40 days for the young to be weaned. They normally mate once a year around here, but we're far enough South for second brood occasionally. If lucky, they might make it to 8 years old, but 1-2 years is much more the norm. 
     Chippies have lots of enemies. Foxes, hawks, owls, large snakes, weasels, and especially cats get many of them. Cats are a particular danger because chipmunks are creatures of habit. They will use the same logs or trails to run on almost every time. Cats figure this out and stalk those routes. The cat might miss several times, but the chipmunk will keep using that little route over and over again, often ending up as a cat kill to bring back to its owner, to eat, or just dump after playing with it a while. They can spend a lot of time ambushing the same area repeatedly that many of our native predators cannot afford to do. 
     I really like these little ground squirrels, always have. These days I occasionally find their greedy little raids a bit much (I mean how much bird seed from the feeder can it really eat?). I also hate it when they find my wild strawberries and serviceberries, as they make off with tons of them. They seem to know that they're safe under the net I put over the plants to keep the robins and starlings at bay on occasion (I've since just given up even trying). But overall I love watching them in my yard. 

A recently weaned chippie wanders away from its burrow for the first time.

     We've been lucky enough to see them raise their young at my house, and there might not be anything cuter. I must admit that in my misspent youth we did some dumb things including trying to catch them. For some reason, we never got bit, though we managed to catch a few, I'm not sure why. I also remember one particular day when one ran up inside the pants leg of my father's best friend and hunting buddy when trying to escape a hunting dog. Yep, that was funny...  So I'l  wish our chippies a good, long sleep, but expect to see their high jinks again in the spring. 



Wednesday, November 18, 2015

Osage Orange: Living Fences of Bow-wood and Horse Apples

The pointed leaf, spiny twigs, and unique fruit of the Osage Orange

     Among the most unusual and recognizable of fruits is the Osage Orange (Maclura pomifera). It goes by a variety of names: Hedge Apple, Horse Apple, Monkey Ball, Yellowwood, Bois D'Arc, Bodark, Bodock, and Bow-wood for examples. It is actually not native to our region, but has been widely planted throughout North America, in all 48 contiguous states and parts of Canada. In fact, I've been told that the national champion is located in Alexandria, Virginia, at River Farm and was a gift from Thomas Jefferson.
     Originally this small tree (it rarely gets to 60') was mostly limited to the Red River drainage in Oklahoma, Texas, and Arkansas. Had it not been for the many virtues that people found in it, it may have eventually gone extinct. Many believe that it originally had its seeds dispersed by megafauna such as giant sloths, mammoths, mastodons, and gomphotheres that fed on its fruits but are now extinct. Very few creatures now feed on it, despite its large fruits, and so it has no real way to disperse its seeds these days. Although squirrels (mostly fox squirrels) and horses (thus the name Horse Apple) occasionally eat them, they do not do so very often and are very inefficient at distributing viable seeds. This is the only surviving member of the Maclura genus. 
     Being dioecious, with male and female flowers on separate plants, only the female trees produce the peculiar fruits. However, it appears that female trees can produce fruit even in the absence of male trees. The fruits produced however lack actual seeds and are not viable. This large, compound fruit is referred to as a syncarp botanically. It looks somewhat like a grainy grapefruit and has a slight citrus smell. The insides are not edible however, exuding a latex substance that is bitter and might even give some people a rash. 
     The tree has yellowish to orange wood that is extremely strong, rot resistant, and flexible. It also takes a polish very well and has long been considered one of the finest woods for bow staves even to this day. Since the tree often grows gnarled and crooked however, it is not always easy to find a straight and knot-free piece that is long enough for use in archery. 
     It is its use for superior bows that gives it several of its common names. Bois D'Arc means "wood of the bow" and was the French term for it upon seeing the Native American Indians use of it. That led to corruptions of that name so that it is sometimes called Bodark, Bodock, and Bow-wood.  The most common name of "Osage Orange" came about by its favored use as a bow material by the Osage tribe. They were famous for their superior and valuable trade bows.
     But they were far from the only people to use if for bows. Other tribes doing so included the Pima, Omaha, Pawnee, Ponca, Seminole, Tewa, Kiowa, and Comanche. Some think that it was so valuable that it was planted far outside its natural range and saved from extinction by the native people. They had other uses for it too. The Pima used for a yellow dye for example (and the tree is sometimes referred to as Yellowwood, though some other trees are also). The Comanche used it for an eye wash as well. 

The twigs and young branches often grow intertwined and are spiny

     But it was some of its other properties that led to it being so widespread. The tree, for example, is very tolerant of a wide range of soil conditions. Not only do the twigs have spines, but each leaf has a spine too. They grow quite fast in the sun, but do not spread very far by seed so as to invade fields. Rather, they can grow very thickly and reproduce next to each other by cloning and sucker growth. They soon can make an almost impenetrable and spiny wall that can be trimmed and pruned. Osage Orange was therefore planted as living fences and windbreaks on many farms before the advent of barbed wire. They could keep stock from wandering, but since they were short, did not shade out too many crops or forage areas. Their use as these living fences and natural wind breaks (promoted heavily in some places) helped this tree spread far and wide.

Each leaf typically has a spine at its base

     These traits were recognized long ago. Francis Porcher in his Civil War treatise on useful plants in the Confederate South praised its use for living fencing. He stated that its presence would "double the real value of any farm it surrounds" while keeping the lands safe "from all thieves, rogues, dogs, wolves, etc." 

An old living fence now has gaps and has fruits strewn underneath and along the whole length of the hedges they now form

     The close-grained and yellowish-orange wood was very much valued, and not just for bow staves. It is considered to be twice as strong as white oak. The timber is extremely rot resistant, even when in contact with ground. Early on, the wood was used for wagon wheels, rail road ties, fence posts, and even police billy-clubs. The timber has some of the highest BTU ratings of any North American wood, so it burns long and extremely hot. Its tendency to spark and throw embers a very far distance should however be taken into account if using it that way. 

The leaves have a slender point and turn yellow in the Fall

     Country lore also has it that the large fruits are a good insect repellent, especially for roaches. Tests however have shown that to be true only for very concentrated extracts from the fruit, so the Osage Oranges themselves would not be very useful for that endeavor. 
     Though few creatures feed on the Hedge Apples themselves, 8 caterpillar species have been documented feeding on the tree. It's real value to wildlife however comes from the shelter the intertwining, spiny branches and leaves provide. Many animals use it for cover and it is a mainstay of hedgerows to this day, surviving as gnarled trees that now have gaps in between that allow many native plants to also grow. 

An Osage Orange

     I have some fond memories of this tree. It was (and still of course is) found along many of the fence rows which I frequented when I was young. My father when taking me hunting as a teen would have me serve some of the duties for the hunting dog we lacked. My brother and I would walk on either side of the hedgerows and flush the game while we hunted. As there were some thickets and the aforementioned spines to be reckoned with, my brother and I would try and find various ways to spook the game for all of us to hunt that would not involve getting into the thickets themselves. The Osage Oranges proved to be just what we needed. We would stop every few yards and load up our game vests with few. That way when we came across a particularly nasty thicket, we could just pull out some of the large fruits to launch into the hedges to flush things out rather than venture in ourselves. So this tree I associate with some of my early outdoor experiences, and I thank it for not just the habitat it provided, but also for saving me from getting poked by sticker bushes. 
     

Tuesday, November 3, 2015

Euonymus Leaf Notcher Moths


A male Euonymus Leaf Notcher Moth (Pryeria sinica), an exotic wasp mimic

     On October 29, 2015, one of our Arlington Regional Master Naturalists, Alison Sheahan, posted a photo and description of numerous moths that appeared in her yard on the master naturalist Google Group. This led to some of speculation as to what these were, since they looked fairly unusual with their clear wings and it was a strange time of year for moths to come out, especially in such large numbers (30-50 of them). They did not fit the description any of the moths I was aware of and so I decided to investigate a bit more.
     It then occurred to me that they might be an exotic species of moth I had read about in an invasive species alert a couple of years before. I asked if I could take a closer look at them and confirm my suspicions. A few days later I visited and was quite sure of what they were, but took some photos and collected some voucher specimens to send to some professional entomologists for confirmation. I then proceeded to ask our Extension Agent for assistance in getting in touch with their entomologist contact and to see what protocols needed to be followed in case they were the invasive pest in the original alert. The visit to our Extension Office provided a nice teachable moment since a Master Gardener class was taking place. This led to an opportunity to talk about invasive species, EDRR (Early Detection, Rapid Response), and how observant citizen scientists can help in detecting potential issues such as these moths could be. The entomologist eventually confirmed my suspicions.

Euonymus Leaf Notchers mating. The males have feathery antennae.

     Euonymus Leaf Notcher Moths were first discovered in North America in 2002 in a Fairfax, Virginia yard where they were causing great damage. The caterpillars were feeding in large numbers. and defoliating the Euonymus shrubs. It took a while before entomologists were able to figure out the exact species, an exotic moth Pryeria sinica. These sporadically showed up in several places in suburban Maryland over the next couple of years, leading Maryland to describe them as invasive species of concern.
     They can apparently survive our winters (they're originally Asian in origin), feed and reproduce in large numbers, are not eaten by many predators, and prefer to feed on various Euonymus species of shrubs, a group of plants used extensively in the landscape industry. They could therefore possibly cause great economic damage. Since we have native Euonymus (Strawberry Bush) and since they can also feed on the very widespread Bittersweet on occasion, their invasive potential is great. They seem to prefer Japanese Euonymus (Japanese Spindle-tree Euonymus japonica), which is what we found them on, but they appeared to also be on the Burning Bush Euonymus shrubs there as well.

Female Euonymus Leaf Notcher laying eggs and an egg mass with protective hairs (modified scales) from their own bodies

     There were several dozen flying that day (November 3) in the warm weather, mating and laying eggs. These moths appear to be wasp mimics, perhaps getting a measure of protection by looking like these stinging insects with their clear, scale-less wings. Euonymus plants have acyanogenic compounds in their leaves protecting them from getting eaten. I think the moths sequester these from when they fed on them as caterpillars and so are somewhat toxic as well. Their body "hairs" (modified scales called setae) likely are defensive as well. When they lay their eggs, they place hairs from their bodies on top to help protect them (see photo). Several moth species that have urticating, protective hairs also cover their eggs and cocoons with them.
     These are daytime flying moths, who come out in great numbers when few other moths or their predators are active. Since they have reduced mouth parts, I'm guessing they don't even feed as adults (it's the caterpillars who feed gregariously and notch the leaves giving them their names).
     Euonymus Leaf Notchers mate near or on their host plants. The females I think send out pheromones which attract the males and other females in large numbers. That is likely why the males have such feathery antennae, to detect the pheromones, and why they were so many together in one location. The females then lay egg masses (about 150 eggs at a time) near the top of pencil-thin Euonymus twigs where they will remain overwinter, hatching in late March or early April.

First instar caterpillars (newly hatched and not molted their first time yet) hang out communally, usually on the underside of the leaf.

     The caterpillars feed communally at first, leaving tell tale notch marks, or completely stripping the plant when in large numbers. They hide under the leaf and can wander far in search of food (as I discovered when a couple got underneath the screen I had them and wandered down the hall).

Multiple instars (molts) of caterpillars.

     Here's a short video of them:
               https://www.youtube.com/watch?edit=vd&v=8UOhfaGmd1w

     Some literature suggests just crushing the eggs or snipping the infected twigs off. That's what we did, but returned in the spring to see what we missed. There were hundreds, with us coming back a couple of times to try and eradicate them as their leaf damage gave them away. I'm raising a few to get photos of their complete life cycle, but well over a hundred have been killed, hoping we can contain or eliminate this threat before they spread.
     While their numbers were still low and since they are not strong fliers, it was a good time to get them, before they got established. But we missed some obviously and will have to keep our efforts up. That is one of the reasons for Early Detection and Rapid Response as a way to deal with new invasives. We may be able to prevent them from getting a good foothold, especially if we get the neighborhood and our local folks to keep an eye out for them. I've since heard that they've also just been discovered in Great Britain. Maybe someone will read this and be able to recognize this invasive moth if it moves into their community regardless of where they live.
     All this began when an informed master naturalist was curious about something new that she had never noticed in her yard before and asked her colleagues to help identify them. It just goes to show that keeping an eye out and taking interest in what is around you might lead to hopefully some timely actions.