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

9-7-2020

Male warblers are flashy and very vocal in the spring. Females are just as abundant, but difficult to photograph.

The forests and marshes near the north shore of Lake Huron in Michigan’s Eastern Upper Peninsula (EUP) are loaded with warblers during May – a total of 27 species. Seventeen species of warblers breed in these areas. Seven more breed further inland in the EUP. 3 more breed exclusively 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 phenomena combines with birds setting up nesting territories in near shore forests to provide plenty of opportunity to photograph females, in addition to the more aggressive and visible males. Peninsulas are especially good places to find the best opportunity. The first 2 date ranges of my spring “Northern Warblers and More” workshop consistently provides this opportunity on the peninsula where I live. Almost all of the images below (all females) were taken there. Opportunity for photographing females off the peninsula are infrequent but also possible. See:  Paul Rossi Spring Workshops

Note that female warblers in the spring often have 2 different looks to their plumage, depending on their age – 1) born the year before or 2) born at least 2 years before. There also can be a slight variance in the look of certain individuals. In ornithology lingo a spring female warbler born 2 or more years before is referred to as an “after second year” female, and is considered an adult bird. A female born the year before is known as “second year” female (even though it isn’t even a year old yet during migration in spring ). Males are classified in the same way and also often have characteristic differences in appearance based on age.

Important: Sometimes a photo is not enough to determine if the bird is “after second year” or “second year”. Ornithologists who band birds for study have the opportunity to have captured birds in hand and carefully study details. They can spread their tail and wing feathers and look at them. Some “second year” birds have tail feather tips of a different shape (relatively narrow and pointed) as compared to “after second year” birds (with broader wing tips), or they have a section of the wing feathers with a different color. These characteristics (as well as others) are often necessary to determine age. So, based on a photo, I often cannot determine the age of a spring warbler.

Also note that by the time warblers make it to Michigan’s Upper Peninsula they have finished acquiring their feathers. Their plumage will not change until they molt in late summer.

Females warblers (below) followed by an asterisk* are species that breed on the peninsula.

Female Magnolia Warbler* – after second year

Female Magnolia Warbler* – after second year

Female Magnolia Warbler* – after second year; more prominent black chest streaking

Female Magnolia Warbler* – after second year; much less prominent black streaks on the chest of this one

Female Magnolia Warbler* – second year; distinctly different and easily recognized; very faint streaking on chest and flanks

Female Canada Warbler – age undetermined

Female Northern Parula*- age undetermined

Female Northern Parula*- age undetermined

Female Northern Parula*- age undetermined

Female Northern Parula*- age undetermined

Female Orange-crowned Warbler – age undetermined

Female Black-throated Green Warbler* – age undetermined

Female Black-throated Green Warbler* – age undetermined

Female Black-throated Green Warbler* – age undetermined

Female Black-throated Green Warbler* – age undetermined

Female Black-throated Green Warbler* – age undetermined

Female Black-throated Green Warbler* – age undetermined; much less flank streaking on this bird

Female Black-throated Green Warbler* – age undetermined

Female Blackburnian Warbler* – second year; in the spring second year females of this species have a grayish cheek and eyebrow, but after second-year females have darker cheeks and eyebrows

Female Blackburnian Warbler* – second year

Female Blackburnian Warbler* – second year

Female Blackburnian Warbler*- after second year; darker cheek and eyebrow (which is not easily distinguished, especially when the bird is not pictured in a profile head position)

Female Blackburnian Warbler*- after second year

Female Blackburnian Warbler*- after second year

Female Blackburnian Warbler*- second year

Female Blackburnian Warbler*- after second year; note the light area above and behind the eye – a variation from normal

Female Black-throated Blue Warbler – after second year; note the blue coloration on this bird (and the next one) – the coloration can range to a greenish color

Female Black-throated Blue Warbler – after second year

Female Black-throated Blue Warbler – second year; note the lack of the white marking on the wing of the second year females of this species.

Female Black-throated Blue Warbler – after second year; landed on the same perch as the bird above, just after it did; this could have been the parent of that bird, and if so, both made it to the Tropics and back, staying together

Female Black and white Warbler* – age undetermined

Female Black and White Warbler*- age undetermined

Female Black and White Warbler*- age undetermined

Female American Redstart* – age undetermined

Female American Redstart* – age undetermined

Female Cape May Warbler* – after second year

Female Cape May Warbler* – after second year

Female Cape May Warbler* – second year; note the distinct grayish appearance, which is typical of a second year female of this species

Female Pine Warbler – after second year

Female Pine Warbler – age undetermined

Female Tennessee Warbler – age undetermined

Female Chestnut-sided Warbler – age undetermined

Female Yellow-rumped Warbler* – after second year, 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 – after second year

Female Blackpoll Warbler – age undetermined

Female Common Yellowthroat – age undetermined

Female Bay-breasted Warbler? Not sure what this is. It could be a partial leucistic second year male. That’s the cool thing about photographing the springtime flocks – you never know when a interesting plumage bird can appear.

Female Bay-breasted Warbler – after second year

Female Bay-breasted Warbler – second year

The above bird shows characteristics of 2 birds – the lower half of the after second year 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 typical female Bay-breasted Warbler that was born the previous year (a second-year bird). 

Female Kirtland’s Warbler – age undetermined; found off the peninsula

Female Brewster’s Warbler – age undetermined; found off the peninsula; a very rare find