Interesting observation Dave. To add to that I had a pair of Bullock's Orioles
nest successfully in a blue spruce tree in my yard a few years back, so they
are indeed adaptable.
Arvind Panjabi 5700' feet, Larimer County, CO On the north slope of Milner Mtn
Mountain mahogany shrubland and grassland
On Friday, July 16, 2021, 09:31:59 AM MDT, DAVID A LEATHERMAN
wrote:
On July 13 a friend of mine and I hiked up Young's Gulch in Poudre Canyon.
Our target was observing and photographing Lewis's Woodpeckers feeding cicadas
to nestlings at one of two nest trees reported by John Shenot, Doug Swartz,
Josh Bruening and maybe others around the 4th of July. We did NOT see any
Lewis's Woodpeckers on the 13th, presumably because at least the lower nest
(1.6 miles up the trail) had fledged and the family dispersed. We did not
hike up to the higher nest reported at 2.8 miles up the trail.
On the way back to the car we heard a begging young bird in a ponderosa pine.
With woodpeckers on our mind, I let the power of "want" convince me this was
maybe a young Lewis's Woodpecker. The location was just below the lower of the
two Lewis's nest reported on the 4th. After several minutes of trying to see
the beggar in the tree, a bird flew into the pine and fed it. The bird was an
adult female Bullock's Oriole. After the feeding, the oriole flew off and down
into the shrubby understory nearby, which my insect-collecting partner and I
knew was rich in food. After a few more visits to the still-hidden beggar, we
had to move on. After thinking, "I've heard that obnoxious noise before", I am
convinced the beggar was a fledged Brown-headed Cowbird.
Cowbirds are reported to parasitize Bullock's Oriole nests. Apparently most of
these attempts are thwarted by parent orioles recognizing the parasite's eggs,
pecking them and throwing them out. But apparently a few cowbird parasitism
attempts are successful. That appears to be the case here. In Catherine
Ortega's BBA II account for Bullock's Oriole she also states the data from BBA
II compared to BBA I suggests Bullock's Orioles are expanding their breeding
range a bit higher in elevation. Young's Gulch is in the 7000' range. Her
account also states they will use ponderosa pine and aspen as nest trees in
addition to the more common usage of riparian poplars. While narrowleaf
cottonwoods were within a tenth of a mile of this location, ponderosa pine and
aspen (and Douglas-fir) were the dominant trees in the immediate vicinity.
I think what we observed was a fairly unusual event: a Bullock's Oriole that
nested in the upper reaches of its breeding range, perhaps in a non-poplar, and
that allowed the scheme of cowbirds to succeed when most oriole parasitism
doesn't.
Dave LeathermanFort Collins
--
--
You received this message because you are subscribed to the Google
Groups "Colorado Birds" group.
To post to this group, send email to cobirds@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/cobirds?hl=en?hl=en
* All posts should be signed with the poster's full name and city. Include bird
species and location in the subject line when appropriate
* Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/
---
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 cobirds+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/cobirds/CY4PR0601MB37637B68445CB0222308FBBDC1119%40CY4PR0601MB3763.namprd06.prod.outlook.com.
--
--
You received this message because you are subscribed to the Google
Groups "Colorado Birds" group.
To post to this group, send email to cobirds@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/cobirds?hl=en?hl=en
* All posts should be signed with the poster's full name and city. Include bird
species and location in the subject line when appropriate
* Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/
---
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 cobirds+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/cobirds/1212030687.535390.1626452524624%40mail.yahoo.com.