By Alison Fetterman, Avian Conservation Biologist and Blake Goll, Education Programs Manager
Introduction | As field biologists living in a human dominated world where wildlife populations have plummeted by 70% in the past 50 years — and birds, in particular, by 30% — the more biodiversity we can record, the higher our hopes. It turns out, bird banders are not alone in this innate need for birds. A recent study by the German Center for Integrative Biodiversity Research shows that connection to nature, especially bird life, is directly linked to our sense of wellbeing. The study linked greater bird diversity to increased life satisfaction for more than 26,000 people; the people who lived near natural areas with a greater diversity of birds were significantly happier.
But birds do more than simply enrich our lives. They are the ultimate environmental bellwether whose population changes can underscore global and local issues ranging from climate change to habitat degradation. At Rushton Woods Preserve and Farm, we strive to model restored landscapes where both people and wildlife thrive. Over 30,000 pounds of chemical-free food is produced annually on just a few acres of regeneratively farmed land within an 86-acre nature preserve. A total of 19,921 birds of 104 species have been documented (through banding) using the Preserve since 2010 (Figure 1).
Here, food and feathers exist in harmony; instead of dominating the land with sights set only on profit, the land is honored with our sights set on feeding the community while bolstering biodiversity and ecosystem health. Birds are free to use the farm to refuel during migration or even nest during breeding, and the farm, in turn, benefits from ecosystem services like pollination and pest control, thanks to the preservation of adjacent native meadows and shrublands. It is in these shrublands where we conduct our migration banding efforts at Rushton Woods Banding Station (RWBS).
SPRING MIGRATION | Aside from the first unseasonably warm week in April, it was largely a cold spring lacking in the southerly winds required to drive migratory birds north to their breeding grounds in a synchronous manner. We experienced our lowest migration capture in our station’s 14 year history: 237 total new birds. Many factors can affect capture including habitat change, global population declines, weather, and effort. Because we only band three days per week and spring migration is rapid (with birds racing to be the first back to the best breeding grounds), it is possible we missed some of the waves of birds moving through. Nonetheless, the data did show delays in spring migration with the highest season capture (49 new birds) occurring on May 9th, one of the latest peaks experienced at RWBS.
Nonetheless, the Northeast’s dazzling diversity of warblers is never more evident than in May when they’ve donned their nuptial plumages and put forth their unique and soulful notes into the collective spring orchestra. Our catch included the wide-eyed Canada Warbler with her bohemian necklace of onyx, the zebra striped Black-and-white Warbler, the calico streaked Cape May Warbler with his striking orange face, the Magnolia Warbler with his stunning black mask and bright yellow throat, and the steel blue cloaked Black-throated Blue Warbler. Few artists could fabricate such a kaleidoscope of patterns and colors.
Some birds return to us year after year, exemplifying the importance of protected habitat, like Rushton Woods Preserve, as places birds can count on for refueling, overwintering, or nesting. One White-throated Sparrow, for example, was originally banded at Rushton in 2021, caught again in spring of 2022, and again in April of 2023. This bird likely overwinters at Rushton each year before returning to its northern breeding grounds in New England or Canada.
Baltimore Orioles are the impresarios of our hedgerows, belting out their whistle songs from the treetops once they return in May. Last spring we captured an adult male that we had originally banded in 2018, making him at least 7 years old! Each spring, he dutifully returns to Rushton to breed after overwintering in similar habitat in the tropics — quite possibly that offered by shade grown coffee farms — relying on the diversity of canopy structure offered by regenerative agricultural practices.
SUMMER BREEDING | Summer is the time when our banders retreat to the coolness of Rushton Woods to study the breeding populations of birds in our woodland for a national effort called MAPS (Monitoring Avian Productivity and Survivorship).
After a low catch of birds in 2022, we were up to a nearly all time high in 2023 with 155 birds of 17 species. We caught a record number of Gray Catbird (59), Carolina Wren (6) and Red-eyed Vireo (7). The former is unexpected as vireos are common breeders of the canopy where we cannot place our nets.
Another tree-top dweller that surprised us last summer was an adult female Scarlet Tanager. As we banded this beautiful yellow bird, her scarlet-colored mate impatiently scolded us from an uncharacteristically low perch. Though we hear males singing each summer, we were unable to fully confirm breeding success until observing this female in hand with a full brood patch (indicating a nest with young). As a State Responsibility Species, Pennsylvania plays a significant role in sustaining the global security of Scarlet Tanagers by hosting 10% of their breeding population.
FALL MIGRATION | The fall procession of southbound neotropical migrants is slow and steady — with birds no bigger than a third of an ounce winging their way along ancient pathways stretching for hundreds of miles in the star studded dark of night. This goes on for almost a month longer than the hurried spring migration, creating multiple waves of species moving through (Figure 2). Like clockwork, as the radiance of the goldenrod fades and the leaves become one with the autumn wind, the bounty of bright warblers morphs into the more muted earth tones of sparrows and kinglets.
It was a relatively warm fall with the first week of September bringing an unprecedented heat wave during which temperatures soared dangerously high for safely operating mist nets. The health of the birds is our highest priority, so the station was closed for the entire week on account of heat for the first time ever. Once the season got underway, however, it turned out to be a successful one with the exception of a record low number of Ovenbirds (only one individual compared to our usual 15-30).
The catch included record high counts for Ruby-crowned Kinglet (113), Swamp Sparrow (33), Nashville Warbler (6), and Hermit Thrush (55). As one of the most intricate songsters of the bird world, the Hermit Thrush’s reedy tremolo echoes throughout woodlands of the mountains and the north. This shy bird is the hardiest of our brown thrushes and least dependent on tropical forests for wintering, often seen throughout the winter in our own PA backyards. For this reason, it is separated from the earlier migrating thrushes in the wave graph (Figure 2).
Birders also help us document the species waves of migration. Last September, a local birder captured a spectacular sight: a Cape May Warbler feasting on cherry tomato juice at Rushton Farm! Most warblers primarily eat insects, but this striped sprite has a specialized, slightly decurved bill that allows it to also probe flowers and fruits for nectar; their long, curled tongues allow them to imbibe from ambrosias not available to other birds —from black cherry and tulip poplar flowers to grapes and tomatoes.
Back at the banding station, we had some rare captures last fall including a Mourning Warbler (only the fourth ever for our banding station) as well as our very first Orange-crowned Warbler in late October.
Orange-crowned Warblers are uncommon in the eastern United States during migration. As one might expect from the similarities of its fine, pointed bill to that of a Cape May Warbler, the Orange-crowned can also feed on nectar and sap, as well as berries and insects. In the west, they are known to dine from Red-naped Sapsucker wells! Its varied diet allows the boreal-nesting Orange-crowned to travel south later than other warblers.
The highest catch of the fall season occurred following a cold front on October 24th with a total of 126 birds of 17 species, including a Winter Wren. This magnificent little creature is a brown ball of plain, speckled feathers that has been gifted with one of the most stunningly spirited songs of the bird world — the ebullience of which has earned him the title of “heart of the forest.” Per unit weight, the Winter Wren actually delivers its song with ten times more power than a crowing rooster!
Last but not least, we ended the season with the first Fox Sparrow since 2017. Unmatched in elegance, the Fox Sparrow is a true bird of the north, nesting from Alaska east to northern Quebec and the Maritimes. Homeowners can provide suitable overwintering habitat for Fox Sparrows by creating or preserving thickets, early successional shrublands, and second-growth forest.
Conclusion | We do not take the temporary care of such wild beauty lightly, and it is the transient presence of these incredible trans-continental animals in our little preserve that casts a hushed reverence on banders as they begin their work in the mystical pre-dawn.
Bird banding is a powerful tool in bird conservation, allowing us to study species abundance and diversity, population patterns, survivorship, and productivity of migratory and breeding birds as well as ecosystem health. For a more in depth look to view Rushton Woods Banding Station (RWBS) Songbird Banding Report 2010-2023 click here.
