sbruenjes Posted June 26, 2020 Share Posted June 26, 2020 I saw these birds at Liberty State Park in Jersey City today. Any help would be greatly appreciated Are these: a boat tailed grackle Forster's tern Yellow warbler? Quote Link to comment Share on other sites More sharing options...
Kevin Posted June 26, 2020 Share Posted June 26, 2020 1 and 3 look good, but I am not sure about 2. 1 Quote Link to comment Share on other sites More sharing options...
Connor Cochrane Posted June 27, 2020 Share Posted June 27, 2020 I think 2 is a Common Tern. Different wing edges and brighter red feet. 1 1 Quote Link to comment Share on other sites More sharing options...
sbruenjes Posted June 27, 2020 Author Share Posted June 27, 2020 Let me see if I have an understanding of differentiating the two. Here is a pic that was previously identified as Forster's. It looks like this bird has more of a reddish beak than the Forsters, and it looks like the wingtips are darker than the Forster's. Are these the best ways to differentiate? Quote Link to comment Share on other sites More sharing options...
Benjamin Posted June 27, 2020 Share Posted June 27, 2020 (edited) Your most recent picture is indeed a Forster's Tern. The difference is very slight, but the bill and feet are more orange, where the Common Tern you posted earlier is a vibrant red. Also, compare the color of the primaries to the color of the rest of the wing. In the Common Tern, notice how the primaries are darker relative to the rest of the wing, while in the Forster's it's much whiter than the rest of the wing. Edited June 27, 2020 by Benjamin 1 1 Quote Link to comment Share on other sites More sharing options...
Tony Leukering Posted June 30, 2020 Share Posted June 30, 2020 On 6/27/2020 at 10:32 AM, Benjamin said: notice how the primaries are darker relative to the rest of the wing, while in the Forster's it's much whiter than the rest of the wing. Note that the outer primaries are contrastingly darker than the one (or two?) inner primary visible in your pic. See crop of pic, below. Common Tern typically shows the outer five primaries contrastingly darker than the inner five primaries due to its odd molt strategy, replacing those blocks of five feathers at different times. The feathers start out pale, due to a pale bloom on them. As the bloom wears off, the underlying darkness of the actual feather shows. The inner primaries are typically molted one more time in a given year than the outer primaries, thus are typically paler. At least, I think that's most of the reason. 1 1 Quote Link to comment Share on other sites More sharing options...
sbruenjes Posted July 1, 2020 Author Share Posted July 1, 2020 Wow, that is an impressive explanation. Thank you! ? Quote Link to comment Share on other sites More sharing options...
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