Tuesday, May 5, 2009

On sharpshins

Joe Nault covered the count for me today, and recorded another pretty good early May flight, similar to what we've been seeing for a number of days now, albeit with fewer buteos. Roughlegs actually did do pretty well today. Many thanks for providing me with a day off, Joe!

Overall count reached 481 today, and included the following raptors: 12 Turkey Vultures, 14 Bald Eagles, 12 Northern Harriers, 380 Sharp-shinned Hawks, 3 Northern Goshawks, 8 Broad-winged Hawks, 5 Red-tailed Hawks, 27 Rough-legged Hawks, 1 Golden Eagle, 16 American Kestrels, and 3 Peregrine Falcons.

Sharp-shinned Hawks still dominate the flight, although their peak flight probably occured last week, when a couple of days had more than 1,000 sharpies. Right now, there's a mix of adults and immatures migrating through Whitefish Point. Soon, the flight will be dominated by juveniles. For practically all raptors, adults precede juveniles in spring. This makes sense, because the adults need to be on territory by a certain time (which differs per species). Show up later, and the best spots to raise a family will be taken by someone else already.

At some other sites I've counted I have seen a two-peak seasonal pattern in Sharp-shinned Hawk migration, with the first peak consisting largely of adults and the second largely of juveniles. This two-peaked pattern appears not to occur, at least not as a rule, at Whitefish Point. Here, as records show, the percentage of juveniles gradually increases as the season progresses, without a secondary peak.

Top bird is an adult male, with fine barring across the chest and a dark red eye. Second bird a subadult female, with body feathers showing a mix of mostly juvenile feathers (streaking) with some adult feathers (barring) growing in, and a yellow-orange eye. Both photos taken today.

1 comment:

  1. once again, your blog has helped me learn some identifying tips! I truly appreciate your postings every day as I have learned more reading your blog here than I have reading all of my bird books!! I look forward to beginning my day checking in online to see what's been flyin' in Paradise. it'll have to do until I can get out in person.
    Stay warm & dry folks!
    Thanx again to all of the 'bird nerds' at Whitefish Point!