by Jamie Bogart, Lloyd Center Research Associate
As the cold weather arrives many people are paying more attention to their backyard bird feeders, and have registered for the “FeederWatch” surveys, a volunteer citizen science program organized by Cornell University to track feeder use from November to April (or starting in 2020 through April during Covid). This fall and winter timeframe is when natural food sources decline for migrant songbirds and feeder use increases.
The Lloyd Center enters its thirteenth FeederWatch season this year, and the fourteenth year of monitoring feeders from April through October (spring and summer). While feeders are less necessary in warmer months, in areas where feeders don’t attract problematic pests they can provide a valuable supplemental food source, as is the case at the Lloyd Center property. The Center had, by 2022, completed a decade of surveys for both periods, spanning 2011 to 2021. Specifically, this was 2011-2020 for the “Lloyd Center surveys” that occur within one year, and the 2011-2012 to 2020-2021 season for Cornell which, like our waterfowl counts, covers two years every winter season. Combined, 21,885 total birds have been counted from 484 surveys, including 11,156 for Cornell (202 surveys), and 10,729 for Lloyd Center (282) surveys. That’s a mean of 45 birds per survey overall, 55 birds per survey for Cornell, 38 birds per survey for Lloyd Center, as expected a higher count during colder months when migrants arrive.
Dominants (top 5) for the Cornell survey over that decade were ranked Mourning Dove, Dark-eyed Junco, American Goldfinch, Tufted Titmouse, and Red-winged Blackbird, familiar species that include two known to flock at feeders in winter, juncos and goldfinches, with finches having irruptive years. The dominants for spring and summer were Common Grackle, Mourning Dove, American Goldfinch, Brown-headed Cowbird, and Tufted Titmouse. This assemblage depicts that some species counted during FeederWatch also breed in the region and are year-round residents, including the Mourning Doves which blanket the ground level any given day of the year, and Tufted Titmouse, arguably the most abundant bird species breeding in our forest. Spring and summer are a time to observe goldfinches in striking breeding plumage and the other winter flocking species, Dark-eyed Junco, is not dominant but present in early spring.
The most obvious difference is the dominance of blackbirds, including Brown-headed Cowbirds and Common Grackle, flocking species during warm months. Of the dominants represented in both surveys, cowbirds are the only species more abundant in spring and summer, and Common Grackle were the most abundant species during those seasons. Cornell identifies grackles as a species forming huge flocks in fall and winter, but which has declined over time for FeederWatch surveys (Cornell FeederWatch winter bird highlights, 2022-2023), so seeing them in warm months now has renewed importance. Red-winged Blackbirds shift from subdominant in spring and summer to dominant in fall and winter when they are more abundant, as the earliest breeding songbird to arrive that visits the feeders in large flocks during late winter.
For subdominant species (top 10) common to both surveys, Black Capped Chickadees not surprisingly increased slightly during colder months, while White-breasted Nuthatches were similar in both surveys. Nuthatches are a watch list species for National Audubon Society Climate Watch surveys which also occur here in winter and summer, with consistent feeder use year-round a sign of a healthy nuthatch population on the property. White-throated Sparrows, the most abundant subdominant species for FeederWatch, were similar to their ground-feeding counterparts the juncos, present but not dominant in spring and summer. Chipping Sparrows are the most abundant sparrow and a borderline subdominant species in our spring-summer rankings.
Both Blue Jays and Northern Cardinals, subdominants in top 10 for spring and summer, and borderline subdominant for fall and winter, have comparable abundance across seasons but not surprisingly are slightly more prevalent at feeders during winter. The discrepancy is greater for Blue Jays due to their tendency to irrupt to some degree in fall and winter, as has occurred this year. For our resident woodpeckers, the Downy makes the FeederWatch top 10 and is considerably more abundant at feeders in winter due to use of suet, while the less abundant, Red-bellied Woodpeckers have showed similar use across seasons. Both species were the most abundant of those not quite reaching dominant status in spring and summer, the Red-bellied Woodpecker for both surveys. Hairy Woodpecker, while not dominant, has been exclusively a fall-winter species. Species not reaching dominant status for either survey, but which were prevalent were House Finch in spring and summer, and American Robin in fall and winter. Species more or exclusively present in either survey included Gray Catbird, Eastern Towhee and Wild Turkey for spring-summer surveys, Song Sparrow, American Crow, and Carolina Wren for fall-winter surveys. Notables for species with at least 10 individuals counted were Pine Siskins, a beloved and irruptive fall migrant only appearing on the Lloyd Center surveys, and American Tree Sparrows, a species seen mostly during winter, which has been exclusive to the FeederWatch fall-winter portion of our survey.
Lloyd Center surveys (including bird bath usage and periodically nectar or fruit sources) yielded from 2011 through 2020 yielded 59 species vs 41 in FeederWatch surveys over the same decade. This includes warbler species not mentioned here that pass through and depicts the diversity of breeding birds that we have on our property. So, as we settle in to watch the feeders become busy in what will soon enough be a falling snow this winter, we can rejoice that once that quick season passes, there are still hungry birds out there, and still more data to collect for this ongoing and important inventory.