US and Canadian Turdidae Nests

I spent most of today researching and cross examining photos of US/Canada Turdidae (thrushes) nests. I got the idea of making posts like this from a comment @beartracker made on the neglect of a nest/egg field guide. I will be posting more of these nest/egg identification posts but for now, I'm starting out small and doing it family by family. So here you go!

Bluebirds-- Genus Salia

There are three species of Salia or bluebirds, the Eastern (S. salia), Western (S. mexicana) and Mountain (S. currucoides). They are fairly easy to identify because they are the only thrushes that nest in cavities or birdboxes. I've even seen a few iNat observations of bluebirds even nesting in hollow metal gate polls. Nests are usually made entirely of fine grasses and straw. Eggs are a vivid blue though white clutches can occur.

Since nesting sites, materials, eggs and even nestlings are nearly, if not, identical among the three bluebirds, most sightings will have to be identified by range. Mountain Bluebird eggs are however on the lighter blue of the spectrum, so darker blue eggs in western US are going to be Western Bluebirds. But since Western Bluebird eggs vary from dark blue to white, all other eggs are best left at genus unless a parent was spotted.

Brooding Periods:
Eastern Bluebird -- Feb-Oct -- 3-5 eggs
Western Bluebird -- Apr-Aug -- 2-8 eggs
Mountain Bluebird -- Apr-Sep -- 4-8 eggs

Eastern Bluebird Eggs (blue and white) along with nearly fledged young.
https://www.inaturalist.org/observations/6891991
https://www.inaturalist.org/observations/21835712
https://www.inaturalist.org/observations/30339752

Western Bluebird Eggs and half-grown nestlings.
https://www.inaturalist.org/observations/25361200
https://www.inaturalist.org/observations/24642607

Mountain Bluebird Eggs (blue and white).
https://www.inaturalist.org/observations/6415727
https://www.inaturalist.org/observations/26904397

Solitaires Myadestes

There's only one breeding species of solitaire in US and it's the Townsend's Solitaire (M. townsendi) of western US. They are the most unique nesting thrush in North America because they are the only thrush that lays white or cream colored eggs with brown speckling, very similar to Passerellidae or New World Sparrows. They make a nest made of pine needles and grasses on top of a cutbank. Forest roads that cut into the mountain are perfect places to look for a nest. Eggs or young can be found in nests between May and July. Here's a couple photos of eggs in nests.

https://www.inaturalist.org/observations/13105721
https://www.inaturalist.org/observations/6842002

Varied Thrush Ixoreus naevius

No need to explain what species this is. unfortunately, no photos showing nests or eggs. Varied Thrush nest are hard to come by, since they nest in dense, thick, wet mature forests. They seem to always nest in young pines close to the trunk with the nest contains being moss, mud and grasses. Eggs are blue with black speckling.

Brown Thrushes Catharus and Hylocichla

There are seven species of brown thrushes breeding in North America and in taxonomic order; Veery (C. fuscescens), Gray-cheeked Thrush (C. mimimus), Bicknell's Thrush (C. bucknelli), Swainson's Thrush (C. ustulatus), Hermit Thrush (C. guttatus) and Wood Thrush (H. mustelina). Since eggs and nests are so similar among the species, I think this graph will better illustrate how to identify nest and eggs.

Ground nest with solid blue eggs -- Veery and Hermit Thrush
Ground nest with blue eggs with speckles -- Swainson's Thrush, Hermit Thrush (speckling rare) and Gray-cheeked Thrush (ground nesting rare)
Bush/tree nest with solid blue eggs -- Hermit Thrush (western US only) and Wood Thrush
Bush/tree nest with blue eggs with speckles -- Gray-cheeked Thrush, Bicknell's Thrush, Swainson's Thrush (tree nesting rare) and Hermit Thrush (speckling rare).

When given this information, you can cut down 7 species, though you probably have less in your state/province, to 2 or 3 species. Keep in mind that breeding behavior for Hermit Thrushes differs geographically with western US birds typically nesting in shrubs or trees while eastern US birds are ground nesters.

Veery nest with eggs, including a cowbird egg. Note that cowbirds strongly parasitized Veery and this can be used for identification.
https://www.inaturalist.org/observations/32429131

Gray-cheeked Thrush nest with incubating mother.
https://macaulaylibrary.org/asset/478063#_ga=2.9695223.374957309.1581564560-1175263981.1555651889

Bicknell's Thrush nestlings.
https://www.inaturalist.org/observations/173108

Swainson's Thrush eggs.
https://www.inaturalist.org/observations/30180919

Hermit Thrush eggs.
https://www.inaturalist.org/observations/11472489
https://www.inaturalist.org/observations/173085

Wood Thrush eggs with cowbird egg.
https://www.inaturalist.org/observations/5613925

American Robin Turdus migratorius

Robins are fairly easy to identify nests. They are only North America thrush that nests in trees with the exception of the Wood Thrush. They also have a tendency to nest on eaves, buildings and wherever urban. The best way to identify their nest from a Wood Thrush is that robin nests are made of grass and mud while Wood Thrush use grass and leaves.

American Robin eggs and a building nest with nearly fledged young.
https://www.inaturalist.org/observations/10746503
https://www.inaturalist.org/observations/3318345

And those are the thrushes of North America. Hope this helps!

Publicado el febrero 18, 2020 05:27 MAÑANA por birdwhisperer