Tuesday, April 18, 2006

Broadwings on the Mountain

Last evening as I drove onto the mountain from work, I saw two broad-winged hawks coming over the mountain, slowing losing altitude as they lost their thermal lift. They circled lazily in the dwindling heat of the day, glided low over the mountain and headed north. Broadwings should be moving through this area now, though it is likely still 4-5 days before the typical peak day of their spring migration.

Broadwings are one of the few hawks that flock together in what we call “kettles” as they migrate. I’ve seen kettles of thousands of birds, though rarely. I’ve more commonly seen kettles of 100 or several hundred. Even these numbers are nothing compared to the tens of thousands that funnel through Veracruz, Mexico, each fall. Broadwing migration is different in other ways too. Weather permitting, they migrate in a narrower time range than most other hawks.

In the fall, in this area, if you want to see kettles of broadwings, you will be most likely to find them in the biggest numbers on September 18. That doesn’t mean you will always find them on that date. Notice I did say weather permitting. Storms hold them up, move them east or west and occasionally hurry them along, but if you look at the most common date for peak migration for the past 50-60 years, September 18 is your best choice if you have to plan vacation weeks in advance. Of course, if you don’t have to plan your time off far in advance, you can always do what I do, which is to study weather reports and watch site reports from the further down the ridge and then take your best guess.

Spring migration is a different animal, though if pressed, I will vote for April 22 as the day most likely to be the season’s peak broadwing day.

Anyway, last night I saw two and was pleased with that since it was nearly 6 p.m. and thus late for these thermally-needy birds to still be flying.

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