A true vagrant?
by Roy Slaterus
On 8 April 2013 a Common Grackle was seen by five observers at migration hot spot Kamperhoek in Flevoland, the Netherlands. It was flying Northeast just like thousands of other birds that day (see here on trektellen.nl for the totals of that day). The observers were not really prepared for such an unexpected bird to appear and it was only after studying photographs that they were convinced of the identification. The bird showed a black plumage, with a contrast between glossy purple head and neck and glossy brown upper- and underparts, a pale eye, strong bill and a very typical ‘grackle tail’. In size it seemed a little bigger than Mistle Thrush. These features point at Bronzed Grackle, the subspecies versicolor – a migrant that breeds in e.g. New England. One of the intriguing questions now is: was it a true vagrant?
Common Grackle, Kamperhoek, Flevoland, the Netherlands, 10:45 8 April 2013 (Roy Slaterus). This photo was made just seconds after the bird was found in strong light at c 450 m off the watch post. The bird seemed to cross the Ketelmeer, like so many other birds, but miraculously changed its path and flew straight to the watch post. Other, and much better photos were then made by one of the other observers.
Go HERE for more photos of the bird at closer range and showing a variety of features.
Thanks very much to team eBird (Chris Wood, Jessie Barry, Marshall Iliff, Brian Sullivan, David Bell) at the Cornell Lab of Ornithology who responded straight back with thoughts on the bird’s identity and superb data on migration timing and distribution of the Common Grackle, especially in NE North America.
eBird team response per Chris Wood
We looked at the photo and agree with that it looks like a Common Grackle — amazing.
You are probably aware that Common Grackle and other blackbirds (Red-winged, Rusty; and Brown-headed Cowbirds) are among the most abundant birds seen when doing visible migration watching in eastern North America. The setting that you describe is perfect.
I’ve attached a graph of frequency for New Brunswick (Common Grackle Frequency NB), Canada (below) that shows the timing of migration for Common Grackle. This shows the percentage of checklists submitted to eBird for New Brunswick where Common Grackle was reported. Most of the province is a bit south of the Netherlands — the migration timing seems spot on for the Netherlands birds with the maximum frequency in NB reached the first two weeks of April. The first migrants arrive in March, and by the third week in March they are frequently seen.
Here is a direct link from which you can also look at birds per hour, high counts etc. [N. B. from M. G. – this is crammed with very cool information Worth an explore and click on all the buttons. Go here.]
I’ve also attached a map of all April records (below) in eBird based on frequency of reports (Common Grackle April all years). Areas where they are most frequently seen are darkest, those where infrequent are palest. You will also notice there are gray squares that indicate where we had complete checklists submitted to eBird with no Common Grackles reported. You can see there are scattered records to the north in April in including Labrador City, NL.
I’ve also included a screen shot (below) of what it looks like when you zoom in and can see individual points (COGR zoom April). Checklists from within the last 30 days appear in red. Since we are limiting this to the current year, this means all red locations are from this April and all blue locations are from previous years. I clicked on the marker at Labrador City, which expanded this box. If you were to click on the checklist link, you could see the entire checklist.
eBird’s Marshall Iliff commented further:
No question whatsoever and I’d be willing to ID as versicolor based on the strong head/body contrast below (see best photos here). It may be a female (not adult male anyway) given the duller underparts (not iridescent bronzy). Remarkable record, and as Chris said, typical behavior for the species. Also as Chris said, this is a great date for vagrancy as almost the entire population is surging northward along the East Coast from mid-Feb to mid-April. Given the Yellow-headed Blackbird records from Europe (very rare on East Coast), it almost seems surprising that this abundant migrant has not been more regular. That said, I think of Brown-headed Cowbird and to a lesser extent Red-winged Blackbird as the most regular blackbirds on ships offshore (and Baltimore Oriole, of course), but have rarely (maybe never) heard of an offshore grackle. Islands a short distance offshore do get grackles.
eBird has a very incomplete picture from Bermuda (total list should be 350+) ad I am shocked that Brown-headed Cowbird is not on the list. No grackle though: click here
Nearer to shore, Monhegan Island is a well covered vagrant/migrant trap off Maine (only 10 mi offshore), although less so in March/April than May and Sep-Oct. Here’s that data as a graph: Click here.
Next: Further information on flight identification of grackles or on vagrancy of Common Grackle is much welcomed and could be sent to roy.slaterus [@] gmail.com .