Spring Migration of Female Warblers in Michigan’s Eastern Upper Peninsula

9-4-2018

The forests and marshes near the north shore of Lake Huron in Michigan’s Eastern Upper Peninsula (EUP) are loaded with warblers during May. 17 species of warblers breed in these areas. 7 more breed further inland in the EUP. 3 more breed further north in Canada.  All of 17 “locals” have many members of their species that migrate further north.

A bounty of midges awaits the migrant warbler flocks when they arrive after their nighttime crossing of Lake Huron, so they often stay for days, especially as winds shift to the north and the nights become cold.  This provides plenty of opportunities to photograph many breeding plumage females, as well as the males. Peninsulas are especially good places to find the migrant flocks. My workshop targets these flocks right on the peninsula where I live.

See:  Paul Rossi Workshops

All of the following images of adult females were taken on that peninsula in May.

Females followed by an asterisk are species that breed on the peninsula.

Female Magnolia Warbler*

Female Northern Parula*

Female Black-throated Green Warbler*

Female Blackburnian Warbler*

Female Black-throated Blue Warbler

Female Black and White Warbler*

Female American Redstart*

Female Cape May Warbler*

Female Pine Warbler

Female Chestnut-sided Warbler

Female Yellow-rumped Warbler* gathering nesting material (deer hair).

This species is the earliest arriving warbler to the peninsula.  If it is warm in mid-May some females can pair with a male and be ready to build a nest during late May.

Female Blackpoll Warbler

Adult Female Bay-breasted Warbler

Second-year female Bay-breasted Warbler

This bird shows characteristics of the 2 birds shown above it – the lower half of the adult female Bay-breasted and the upper half of the female Blackpoll,  so I initially thought it was a hybrid between the 2 species (which does occur).  Note that the Blackpoll and Bay-breasted are structurally identical.  But it is a female Bay-breasted Warbler that was born the previous year ( a second-year bird).  I thought fall warblers were the confusing ones, but in the spring identification can be difficult as well.