I had a similar, but much smaller cluster of Swainson's Hawks at the second stop (near intersection of C.R. 42 & N, ~ 15 miles east and a couple miles north of Campo) of my Edler BBS route in Baca County on June 1st. Had 8 birds on a center pivot plus several more in the air, on poles, etc. Mostly immatures. Usually have a few immatures along the route and several nest sites, but never had seen anything like this on my route before. Makes me wonder if folks in other regions of their migration belt are seeing similar late numbers that might indicate something retarded the migration; or really low numbers that might indicate something pushed the birds toward our region. It'll be interesting to see if these birds stick around for the summer or were just moving through. Kevin Corwin west Centennial
On Saturday, June 3, 2017 at 2:01:18 PM UTC-6, Dave Leatherman wrote: > > Ran the Lamar Breeding Bird Survey (BBS) route yesterday with assistance > from Janeal. The route starts at Prowers MM/13 northeast of town, goes > north to Prowers SS then east and north, ending at Kiowa 61/K several miles > sse of Chivington . Had black rail calling on SS about a mile e of 13, a > first for the route. Other interesting species were dickcissels, good > numbers of Cassin's sparrows, orchard orioles on a few riparian stops, and > this: 168 Swainson's Hawks over the last 22 stops, with 106 of them on one > stop! I do not know how to interpret this. It would seem to be one of two > things: a very late kettle still coming north because of the late spring > storms OR families populated with already-fledged young staging for their > return flight south later this summer. Great, great majority of birds were > immatures. Timing seems odd for either scenario. Maybe analysis of eBird > data would shed light on which it is. The birds were mostly on the ground > in fallow wheat and/or corn fields. There is currently a notable shortage > of grasshoppers on the eastern plains of CO. This may change as the season > progresses but it could be that at present this largely insectivorous buteo > is being forced into habitats mostly free of vegetation in order to make > available prey items (including big tenebrionid beetles) more visible > (similar to what mountain plovers do with their habitat selection). Of > note, we detected zero mountain plovers on the entire route and they are > usually present on 5-6 stops. > > > If anyone has input on the Swainson's hawk phenomenon, I'm all ears. > Please share with the whole group. Thank you. > > > Dave Leatherman > > Fort Collins > -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/5fb5d7d6-fda8-474b-bcaa-a6198af0ea85%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
