The Steller’s sea eagle that visited us here in Maine for over two months has moved on to the north shore of Nova Scotia. Using all the eBird records of this phenomenal bird, I’ve been having some fun with the numbers.
To start with, Steller’s sea eagle is not a common bird, with the current population estimated between 4,600 to 5,100 individuals with around 1,900 breeding pairs. These eagles are found in the Far East, nesting on the shores of the Bering Sea and the Sea of Okhotsk. They winter in Korea, Japan and southeastern Russia (Ussuriland).
There are 79 eBird records for Steller’s sea eagle in Alaska over the years. But the one we hosted in Maine was a real oddity. It has been wandering in eastern North America for over a year. There is even a single sighting in Texas that may have been the same bird.
After visiting Quebec, New Brunswick and Nova Scotia earlier in 2021, the eagle put in an appearance in inland Massachusetts in mid-December. It disappeared just before Christmas. Birders throughout the Northeast were keen to know where it would appear next.
On Dec. 30, the Steller’s sea eagle was spotted at Five Islands in Georgetown by Linda Tharp, a local resident. The chase was on. Hordes of birders descended on Five Islands the following day and most got to see the bird. Nearly as many visited the area on New Year’s Day.
There were 277 eBird records of the eagle on Dec. 31, 156 records on Jan. 1 and 129 records on Jan. 2. The sea eagle became harder to see after that, sighted on only 16 days between Jan. 3 and March 4.
Curious to know how many people got to see the Steller’s sea eagle (a life bird for most everyone, I’m sure), I summed all the eBird records and determined that there are 1,198 records of the sea eagle in Maine.
However, those 1,198 records don’t translate into 1,198 birders. Some birders got to see the sea eagle on multiple dates, and five intrepid birders saw the bird on five different days. Correcting for multiple observations, I found that 1,024 eBirders got to see the Steller’s sea eagle in Maine.
However, this total is an underestimate. There are a significant number of serious birders who do not use eBird. When my wife and I went on Jan. 1 to see the bird, I noticed lots of families there with young kids. Certainly, most of those kids do not have eBird accounts. Finally, there were people there because it was a happening, not because of an abiding interest in birds. Those people surely did not have eBird accounts.
So, we can be sure that well over 1,024 people got to see the Steller’s sea eagle in Maine. If we add the number of eBirders who saw the same bird in other states or provinces, we get 1,263 birders. That includes 12 in New Brunswick, 45 in Nova Scotia, 52 in Quebec, 129 in Massachusetts and one in Texas.
Let’s look at the total of all the eBird records for the six regions where our peregrinating sea eagle has been seen. That total is 1,545 records. The sum of all the Steller’s sea eagle records anywhere in the world is 4,445. That means that one bird accounts for 34.7% of all the eBird records. Japan has the most Steller’s sea eagle records with 2,074. The U.S. is second, mainly due to a single bird. Russia has only 374 eBird records, but I am sure that is because Russian ornithologists and birders haven’t embraced eBird to the same extent as we have in North America.
It would have been fun to determine how many of the birders who saw the Georgetown sea eagle came from out of state. Understandably, eBird anonymizes the records sent to researchers, so it is not possible to know each eBirder’s name or state/province of residence.
Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at
whwilson@colby.edu
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