Nelson's Gull

Today, Sandy Hook was shrouded in dense fog, which gave me a day off from hawk counting and provided me with an opportunity to scour the Hook in the mist for birds. The northern tip of the Hook is never so wildly beautiful and mysterious (and devoid of people) as in dense fog.

At the very tip (the "False Hook") I found this unusual-looking gull. At first I thought it was a Glaucous Gull, but I quickly realized the wingtips were too dark for that species. Somehow the bird seemed too light to be a Herring Gull. Not knowing what I was looking at, I decided to try for some photos.

I now believe it to be a first cycle 'Nelson's Gull', i.e. a hybrid between Glaucous Gull and American Herring Gull. It shows a mix of characters from both species, and Howell & Dunn's authoritative Gulls of the Americas (2007) lists that combination under the header "widespread hybrids". Confirmed interbreeding occurs in the Mackenzie Delta, Northern Territories, Canada (Howell & Dunn 2007), a potential source for this individual.

I also considered first cycle Slaty-backed Gull and first cycle Thayer's Gull, but Glaucous Gull x American Herring Gull seems a better fit. Especially the crisply bicolored 'Glaucous type' bill does not fit first cycle birds of either species, but is good for 'Nelson's Gull'. There's other disqualifying field marks. I do confess I am not a larophile, so I welcome discussion of the finer ID points from the initiated.

Cited literature:
Howell, Steve N.G. & Dunn, Jon (2007) Gulls of the Americas. Peterson Reference Series, Houghton Mifflin Company, New York.

First wave of warblers

Palm Warbler

The first wave of warbler migration has reached Sandy Hook: yesterday there were tens if not hundreds of Palm Warblers throughout the Hook, with some Pine Warblers here and there. Another warbler - Common Yellowthroat - was heard singing from across North Pond both Sunday and Monday mornings, but on Tuesday appeared to have moved on. I found two American Bitterns in its place. Myrtle (Yellow-rumped) Warblers have been around a bit longer, in fluctuating numbers. We haven't really had a big wave of them yet.

adult female Pine Warbler

Orange-crowned Warbler and Black-and-white Warbler have also been reported, and very soon warbler variety will pick up even more, as the other species cannot be far behind now. Possibly the next warm front will bring them to Sandy Hook.

Right now, the Hook is dripping with Slate-colored Juncos, Ruby-crowned Kinglets, Palm Warblers, Hermit Thrushes, Blue-gray Gnatcatchers, Savannah Sparrows, Chipping Sparrows, and Song Sparrows. All these birds are here in good numbers at the moment, and are easily seen.

Great kestrel flight

The second warm front in a fairly short time brought a second wave of American Kestrels passing Sandy Hook yesterday. On the 6th I had 67 kestrels; yesterday I got to 155. This is a respectable number, but by no means a record, for 2009 had 226 and 2008 had 179 for single day counts at Sandy Hook. Most recent years, however, the peak flight of the American Kestrel here has been double, not triple digits. This species is in decline throughout the Northeast, even though largely sedentary urban populations seem to be doing fine.

Like other falcons, American Kestrels are often midday or afternoon flyers, and indeed the majority of these birds passed in the afternoon.

Good early April hawk flight

A pretty good early April hawk flight was seen at Sandy Hook today, with good overall variety and a particular strong showing of American Kestrel. Several Red-shouldered Hawks, including at least two adults (one of which is pictured above), were noted, although none were seen leaving the Hook. That's good news for those of my readers who want to see Red-shouldered Hawks but weren't able to make it to Sandy Hook today.

The falcons of course did not linger. Most of the falcon flight was made up of American Kestrels, but there were a few Merlins also and even a Peregrine Falcon.

Last year, the peak flight of American Kestrel occurred on April 6, back then with 85. Today, exactly a year later, I got to 67 kestrels. Last year, I had a small wave of first migrant Merlins also around this time, with 13 on the 6th, 8 on the 7th and 21 on the 8th. That was 42 Merlins in three days - a wave that, curiously, no other hawk watch recorded. This year, I had 13 Merlins on the 4th, none during the 2 hours of counting on the 5th, and then today just 3. It will be interesting to see if this wave of kestrels is followed by a smaller wave of Merlins in the days ahead…

Browse last year's Merlin posts here.

Northern Saw-whet Owl

I got up a little earlier than usual this morning, to help bird bander Tom Brown with some Northern Saw-whet Owl banding here on Sandy Hook. Tom has been banding songbirds on the Hook and elsewhere in the metropolitan area for years, and last fall started banding at night here on Sandy Hook with an audio lure for saw-whets. He caught more than he expected back then, and this spring is trying again for saw-whets. The individual shown above was his third this spring. We aged it as a second year bird, so born last year.

We wondered if severe winter weather was responsible for the contrast between the fall and spring numbers of saw-whets.