Our Changing Birds
“The only constant in life is change.” Whether you consider that ancient wisdom or just trite, it’s true. It’s certainly true of birds, whether it’s the change in species day to day during migration or the change in populations over time. At this time of year, the local bird community can change significantly overnight as migrants arrive en masse from points south. Towhees are here now, but were scarce a little over a week ago. As of an hour ago, time of writing, a hummingbird is back in my yard. But lately, by which I mean today while trying to come up with a topic, I’ve been thinking about change over those longer time scales, changes in populations. And I just had to look at this week’s rare bird report to see some obvious examples.
For me, Sandhill Cranes always evoked far-off wild places like Bosque de Apache refuge in New Mexico, the Platte River of Nebraska, or Georgia’s Okeefenokee Swamp where I saw my first ones 25 years ago, a loudly bugling family group that crossed the trail in front of me, stopping my breath. But they’ve been steadily increasing in the northeast both as a visitor and, now, a breeding species, with recent nesting records in both eastern and western MA. When one took to walking around suburban yards in Chatham and Barnstable a couple of years ago, it took some of the shine off their wild pedigree in my mind. But they are still a spectacular bird, and the sightings from different parts of Truro a few days ago are nevertheless exciting.
Black Vultures are mainly southern birds - like really southern, as in they are most common in Central and South America. They were regular into northern New Jersey 20 years ago but still rare in Massachusetts. In just a few years they’ve become commonplace, such that the several sightings between Falmouth and Provincetown this past week barely register on the rare bird report. In fact, a small flock wintered in Bourne this year, something unimaginable less than a decade ago.
Like Sandhill Cranes, ravens were birds of distant wildernesses when I was a kid, but that has changed rapidly in the last 10 years. I checked the eBird database for April reports Common Raven on Cape Cod over time. In April of 2010, there was a single sighting. In 2015, there were five, and this year there have been at least 40 so far this month. Part of this is explained by more birders using eBird, but overwhelmingly it’s that this species has fully colonized, or recolonized, our peninsula after centuries of absence. They nest now from Sandwich to Provincetown and everywhere in between, less than 10 years after the first nest was discovered on a catwalk at the canal power plant.
On even longer time scales, birds we take for granted in our yards like Carolina Wrens and Red-bellied Woodpeckers were rare or absent when I was a kid growing up in Brockton in the 1980s. Titmice were all but unheard of before the 1960s, and even cardinals were rare southern birds at the start of the 20th century.
As we’ve seen with ravens, Bald Eagles, and other species, once the change starts, it can progress very quickly. So to paraphrase and perhaps mangle that old saying that Mark Twain may or may not have coined, if you don’t like the birds on Cape Cod, wait a few years.