Monday, February 13, 2017

Carolina Wren

     Carolina Wrens (Thryothorus ludovicianus) are common birds who are beneficiaries of warming temperatures. They've steadily been spreading their range northwards and westwards now for decades. Their ranges quickly contract when hit by harsh weather. Ten subspecies are now recognized, 6 North of Mexico. Their scientific name translates from Greek and Latin into "reed jumper" "of Louisiana." Of the 9 wren species, Carolina's are the second largest in the USA, with males being slightly larger than females on average.
     These 5.5 inch birds are quite active. They have a white eye brow and tip their tails up, specially when alarmed. They're also quite vociferous, with the male giving a distinctive "Teakettle, Teakettle, Teakettle" song regardless of season. Both males and females also give alarm, scold and other calls year round, the pair often vocalizing together. Here's an example of a male giving its call:


     Here is another giving various scolding calls:


     Pairs often mate for life and defend their territories from other wrens and even other birds while nesting. Both sexes build the nest, though the female chooses the nest site and usually puts the finishing touches. Nest sites tend to be less than 10' high and are often slightly domed, but that's where the similarities end. They've been known to nest in all sorts of unusual places. While they may utilize cavities and bird boxes, they will also nest in all sorts of other locations. I've found them in flower pots (specially if they've been tipped sideways), mail boxes, and air vents. They've also been documented in brush piles, pails, coffee pots, baskets, roots, old hornet's nests, dense shrubbery, discarded cups, brush piles, pockets of clothes, and pails, among others.
     The female lays 4-8 creamy eggs on average and takes on the majority of the incubation. In 12-14 days, the eggs hatch. In about 2 weeks, the young fledge. The male often finishes raising the young while the female starts to nest again. Two to three broods a year are normal. They are common victims of brood parasitism by cowbirds, suffering 25% nest loss in some locations, though most of these are for the first nesting. Wrens often have better success in subsequent nesting attempts that same year.

A newly fledged wren.
     Wrens feed mostly on insects and invertebrates, 94% of their food consisting of these, particularly while nesting. In many locations, spiders make up a significant portion of their diet. With a bit of luck, they have been known to live over 7 years.
     Being year round residents and being so vocal, these are birds I enjoy in all seasons. They are not shy and make their presence known all year long. No wonder they have been chosen to be the state birds for South Carolina.

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