I recently learned about the Audubon Christmas Bird Count↗ from Jer Thorpe's bird data visualization course↗. I searched the data for Brooklyn, and I was shocked to see that the Brant sightings outweighed any other bird by nearly 2-fold.

Data sourced from Cornell's eBird

The Brant, despite it's duck-like appearance, is a goose that migrates from the Arctic to the US East Coast every year. It thrives in astonishing temperatures reaching as low as 36 degrees Fahrenheit. While they are super cute, it's peculiar that they'd account for so much of the total birds seen on Christmas day.

Look how cute by Mathew Schwartz on Unsplash

My instinct was to investigate why the bird count was so alarmingly high and it looks like the proportion of Brant sightings to other birds has indeed risen. We use proportion here because the total number of bird loggers has also risen, so it's proportion we need.

Data sourced from Cornell's eBird

Given the widespread effects of climate change, I thought "something is probably up." I acquired data from the US Fish and Wildlife Service, Migratory Birds Division↗ and instead found that while it was a good guess, the population has been relatively steady year over year, placing it on the 'least concern' for conservation list. Interestingly, there was a major drop in population after consecutive brutal Arctic winters in 1976-1977↗, after which the population dropped to ~40k. The population recovered to its former glory of 120k+ due in part to swift implementation of hunting regulations.

Data sourced from US Fish and Wildlife Service, Migratory Birds Division

So we know that Atlantic Brant sightings have gone up, but the population has remained steady. This means that more of the population is present or migrating to Brooklyn than ever before. The top two states for Brant sightings during the winter migration are NJ and NY. Interestingly, NJ started out as one of the top migratory stops for these birds but has seen a steep decline, while NY is seeing a steep increase. Researchers predict that the swap from NJ to NY was seen in major part due to the harsh winters of 1976-1977, specifically the birds continued the behavior of migrating further inland in New York City to avoid extreme winters.

Data sourced from Cornell's eBird