Chickadee with nest material (Photos by Don Reimer)
Chickadee with nest material (Photos by Don Reimer)
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BREEEP! BREEEP! That’s not the sound of a beeping vehicle I was hearing. No, it’s that noisy Great Crested Flycatcher that arrives behind my house each mid-May. A relatively large, vocal species that utilizes natural tree cavities, abandoned woodpecker holes or occasional bird houses, this particular flycatcher prefers the same backyard hardwood tree each year. As the season progresses, I’ll be watching for definite signs of confirmed breeding activity from him. The Great Crested species commonly incorporates shed snake skins or bits of cellophane into their nests. At this juncture, my Great Crested friend has already achieved Probable Breeding status by visiting a probable nesting site.

This spring I’ve paid much closer attention to specific clues of bird nesting behavior due to my involvement with the five-year Maine Bird Atlas project. So far, I’ve collected confirmed breeding evidence for a number of early nesting species: Bald Eagle, American Crow, Fish Crow, Common Grackle, two Merlin nests, Song Sparrow, American Robin, Eastern Bluebird and Tree Swallow, to name a few.

Spring migration is still under way, however, and many birds are simply passing through our region to nest elsewhere farther north. The Bird Atlas protocols account for this timing factor by providing “safe dates” for all species. Safe dates reflect the actual periods when a species is most likely to nest. A recent Monhegan weekend only served to highlight the continuing migration phenomenon as legions of hungry warblers scavenged through branches in search of insect fare. After a couple days of intense feeding activity, many warblers and other songbirds pushed northward.

Two species of crossbills (Red and White-winged) seen on the island throughout that weekend are outliers to the predictable nesting timeframes of most songbirds. Crossbills are nomadic species that wander across vast boreal forest regions to feed on crops of cone seeds. Upon locating a suitably cone-rich forest sector, crossbills pause temporarily to nest before shifting to new areas. Capable of nesting in any given month of the year, crossbill “safe dates” are generally April or earlier into August.



 




Let me share two examples of recently confirmed breeding data from my atlassing project. On May 11, I enjoyed face-to-face encounters with a Black-Capped Chickadee pair in a wooded grove. Both chickadee mates excavate the nest hole (taking about a week), but it’s the female that lines the interior cavity with fur, hair, moss, feathers and cottony fibers. The female chickadee was perched within 20 feet of me, her bill crammed full of brown deer hair. After depositing that hair, she re-landed near my feet to snatch a sheath of choice white deer hairs from the leafy ground litter. Deer hairs are a smart selection since they are hollow-cored and provide high insulative value. Once the cavity nest is completed, the male chickadee will feed his mate during her 12- to 13-day incubation process.

On May 14, I observed a female Ovenbird warbler as she carried fine grasses to a ground nesting location in shaded spruce forest. Walking with a persistently cocked tail and deliberate gait along the forest floor, she picked and arranged dried leaves near a mossy mound to construct her namesake dome-shaped nest. Despite my best visual surveillance efforts, the actual nesting depression was obscured from view. We humans are restricted from seeing all of nature’s intimate ways. Other birds, however, may take advantage of the secretive Ovenbird’s nest location. Brown-Headed Cowbirds parasitize many nests, but Ovenbird nestlings often survive sharing their nest with the bigger, more aggressive cowbird chicks.