GCBO Bird of the Month

Mourning Warbler

by Mike Williams


Geography/Habitat: 


The Mourning Warbler, (Oporornis Philadelphia), first described by Scottish ornithologist Alexander Wilson close to Philadelphia in 1810, is monotypic but forms a superspecies with MacGillivray’s Warbler and hybridizes with both this and the Connecticut Warbler. Note some authorities place the Mourning Warbler, (and its allies), in the genus Geothlypis which contains Yellowthroats etc. 


Mourning Warblers breed in Central and East Canada and the North-Eastern US around the Great Lakes area and winter in Panama and Northwestern South America. Spring migration is through the Central and Eastern US. Fall migration is typically further East. Note it is primarily a circum-gulf migrant and when over water hugs the coast.


Preferred habitats are dense thickets especially blackberry thickets and briars, but any dense damp woodlands are suitable. In migration any dense low bushes are used. Note Mourning Warblers are very skulky and hard to see.

Breeding season is June to August and 3 to 5 white brown spotted eggs are laid in a cup shaped nest low to or even on the ground. The nest is constructed of dead leaves and vegetation lined with rootlets and hair. Incubation is typically 12 days with a further 10 days before fledging.


Mourning Warblers eat most insects and spiders usually gleaned from foliage and leaf litter from an established feeding territory. Note they will sometimes take sugar water and fruit pieces from feeders.


Identification:


A middle-sized warbler with an olive-green back, yellow underparts and a distinctive gray hood that is darker around a pink bill with a black upper breast. The female is similar but duller and sometimes has a thin pale eye ring. The lack of bold white eye arcs or ring distinguishes it from the other closely related species of the genus. 

Its song is a cheery “teedle-teedle, turtle turtle” and solitary chip note repeated when agitated.



Interesting Facts:


• The female Mourning Warbler eats the eggshells after the chicks hatch. 

• If predators approach, both parents will feign a broken wing and try to lead them way from the nest

• A group of warblers is known as a Wake – very apt in this case!


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