Date: 4/3/17 8:22 am From: coloradodipper via Colorado Birds <cobirds...> Subject: [cobirds] Raptor (and other) migration at Matthews-Winters Park (JeffCo) - 2 April
I spent an hour watching for raptor migrants from Matthews-Winters Park (across Hwy 93 from Dinosaur Ridge, just south of I-70) from about 1 pm to about 2 pm. Had I noticed a significant amount of such migration, I was prepared to make the trudge up to the hawkwatch lookout on Dinosaur Ridge.
My eBird checklist
The first migrant I found was a single White-throated Swift winging north along the east flank of the ridgeline that includes Mt. Morrison, perhaps 10 minutes into my vigil. About ten minutes later, I found a flock of five American White Pelicans high and distant west of the Mt. Morrison ridgeline, heading north. I found my first raptor migrant, a Turkey Vulture, at 13:44 crossing the east face of Mt. Morrison and continuing north across I-70.
Ten minutes later, there was a flurry of raptor migration activity. At 13:54 I found an adult Red-tailed Hawk circling south of Mt. Morrison. It proceeded to gain altitude and then streamed north over the top of the mountain, but just over the ridgeline on the west side of the mountain. It glided north to about halfway between Mt. Morrison and I-70 and then circled up again. While I was watching it re-gain the altitude lost on the long glide, a female Cooper's Hawk went zipping past behind it (farther west), heading north at 13:58. I returned to watching the Red-tailed Hawk, only to find a male Cooper's Hawk (13:59) circling near the Red-tailed, and then gliding off to the north. The Red-tailed finally crossed I-70 at 14:02 continuing north. That spurt of migrants almost got me climbing up to the hawkwatch, but work started calling in my mind's ear, so headed back to my temporary home in Arvada.
These four raptor migrants, found in a span of 15 minutes, were following typical raptor-migrant flight lines for the area: one was between Hwy 93 and Mt. Morrison (though closer to the mtn.), three were over the west flank of the Mt. Morrison ridgeline -- the line taken by the majority of raptors that I have counted from Dinosaur Ridge in my two seasons plus counting there.