happy belated valentine’s day! last month, i found a herring gull that was born… on a roof across the street from the restaurant in portland, maine where brittany and i ate the night we got engaged. awwwww… :)
this gull interested me beyond the fortuitousness, of course. while herring gulls are well-known city slickers, they’re also native shorebirds, breeding on coasts and flat areas across the country. some, like this gull, have eschewed beach-side habitats and started their lives on roofs instead. and this is especially interesting in the context of this species’ declining population.
but first, a word on bird banding. i learned where our roofgull came from thanks to a band around its leg. banding dates back to john james audubon experiments in the 19th century. it’s a way that ornithologists can track individual birds year-over-year, and in some cases, learn where the birds go during the nonbreeding season. finding a banded bird is one of birding’s grand prizes in my opinion, since it can reveal stories otherwise hidden in a sea of identical-looking creatures. we found this bird during a gull identification class i was teaching at coney island and noticed its black-on-orange plastic band, which read “DJJ.” i submitted that band to reportband.gov, the website of the usgs bird banding laboratory, and received a certificate within a few days.
djj—full name 1286-13385 DJJ—was too young to fly when a team from the university of new england banded it on june 15, 2023. djj was born on the roof of a parking garage on the corner of pearl street and fore street in portland, maine. the restaurant is a farm-to-table place called hugo’s that had a very nice tasting menu, and the most memorable course was the dessert which featured cake and ice cream made from root vegetables.
this gull was banded as part of a broader effort to study gulls nesting on urban rooftops to understand the costs and benefits. waterbirds nesting on rooftops isn’t a new thing—there are records of european herring gulls nesting on roofs around the black sea dating to 1894. the first records of herring gulls nesting on roofs in north america come from the early 1970s in canada. those colonies have grown quickly since—by the mid 1990s, approximately 4% of the great lakes’ herring gulls were born on rooftops, according to a 2016 paper by noah perlut from the university of new england and his team.
but why? scientists have long figured that gulls choose rooftops when their populations grow too quickly, picking worse habitat in the absence of prime habitat. others have suggested, and some studies have shown, that rooftop habitat might be better habitat given the abundance of nearby human food and extra space to spread out. perlut’s team was trying to answer this question for the herring gulls nesting on rooftops in portland, maine, in the context of the species’ population decline—the state’s herring gull population fell by 5% annually from 1966 to 2012.
perlut’s team bands the birds on the rooftops and does analyses like measuring the number of eggs and the volume of the eggs in the nest, and tracking how many of the chicks survive their first month. they also compare those measurements to those from more traditional herring gull habitat, a beach colony on nearby appledore island.
in that 2016 paper, the team found that the rooftop gulls laid fewer eggs and had lower hatching success than those on the island colony—but the rooftop chicks that did hatch were more likely to survive to day 30 than the island gulls. this suggests that even amid less competition for nest sites on the traditional island habitats due to population declines, gulls might be choosing rooftops anyway because they’re equally good habitat.
here in new york city, we’ve got our share of roof-nesting gulls, too. the javits center hosts a colony with at least 150 pairs of herring gulls. they’re banded as part of a scientific operation run by nyc audubon, who also works with the javits center to ensure the birds don’t nest in places where they’ll cause conflict with people.
of course, that’s a major challenge with roof nesting gulls: while i’m enamored with our gulls and would welcome them on any roof, other people don’t like them there. loud, brazen, and messy gulls are not especially thoughtful tenants and can draw the ire of locals who seek to remove them, as detailed in this nice newengland.com piece on perlut’s team’s work. and it seems gulls have only increased their roof-nesting behavior in recent years—so those conflicts are sure to increase.
herring gulls have pretty complex movements, so it’s not clear where our gull will go next. more often than not, young herring gulls choose new places to breed. perhaps this bird, too, will find a roof to breed on. and maybe that roof will be another important place from my life. who knows :)
postscript
when we do a good job at work, we give each other “blue points” (or as i call them, “good boy points”). for a long time, i thought they were relatively worthless, but back in december i realized that they could be redeemed for flights. i had more than enough points for a flight to costa rica, so i booked a five-day trip on a whim. the trip was awesome thanks to the planning of my friend jorge, who leads tours down there. the rarest thing we saw was the cacomistle, a nocturnal relative of the raccoon that inhabits central america but in costa rica can only be found in the highest-quality cloud forest. jorge had coincidentally been talking about how much he’d wanted to see one the night before—making it an excellent lifer for both of us. we also saw incredible birds, including major targets of mine like the ocellated antbird, unspotted saw-whet owl, ochraceous pewee, and silvery-throated jay. i’ve included a few photo highlights below. there are obviously way more highlights, all detailed in my trip report here.
