Wednesday, September 30, 2009

Excellent Hawk Flight, Low Number but High Quality Landbirds, and How Fast is a Peregrine?

An excellent hawk flight was underway this morning when I left the platform around 10:30 a.m. - one observer later remarked on having 7 species of raptors in one binocular field of view! This is not surprising given the west winds.

Land bird numbers seemed lowish, possibly because showers to the north blocked nocturnal migration (the high wind didn't help, either), but I heard of Connecticut and Wilson's Warblers and Winter Wren seen on the trails at Higbee Beach, and a delightfully cooperative pair of Cape May Warblers entertained many people in the cedars next to the pavilion near the hawk watch. I use the word pair intentionally, since a) it was a male and female, b) they stayed next to each other much of the time, and c) even touched bills at one point, possibly in a food exchange. Like most passerines, Cape May Warblers are thought to be seasonally monogamous, i.e. one male mates with one female for one breeding season (extra-pair copulations have been shown to be common in some species using this system), and I'm not really suggesting these two were traveling together, but perhaps they were.

I was over at Hidden Valley checking on the condition of the big fields there, which were sprayed last spring to control invasive woody plants prior to additional management. Bird activity in the fields was limited - I had Eastern Meadowlark in the back of my mind since one was seen at Morning Flight yesterday - but there were over a dozen Wood Ducks along the trail going into the woods at the very back (southwest) end of the fields. Also of note, funny enough, was the aggregation of 80 plus American Crows in the field across from the parking lot.

On the speedy Peregrine, swing counter Doug Gochfeld asked me how long I thought it took a Peregrine Falcon to cross the bay. He was setting me up, since he already knew the answer from staying in contact with Forrest over at Cape Henlopen, DE on occasional specific birds they both see. One Peregrine made the crossing in 16 minutes!!! That kicks the ferry's butt. Straight line distance from Cape May to Cape Henlopen is about 12 miles. Doug and Forrest clocked another Peregrine at 44 minutes - but it showed up in Cape Henlopen carrying prey! It's hard to know for absolute sure whether these are the same birds, since there's always the chance that a Peregrine could get to Cape Henlopen without being seen from the Cape May platform, but it seems likely they are the same.

Speed of flight can be a very useful bird i.d. clue, especially if you are familiar with a location and can accurately judge how long it is taking a bird to cover ground. Peregrines are deceptively fast when they are trying to make time, faster than Merlins despite the p-bird's slower wingbeat. Merlins in turn are way faster than kestrels. Like any behavioral clue, this has to be applied with caution because Merlins almost always seem to be trying to cover ground, while the other two falcons often take a more leisurely approach.

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