One of my Breeding Bird Survey (BBS) routes is Guanella Pass, beginning above Georgetown in Clear Creek and proceeding along the Guanella Pass Scenic Byway over the pass and down to Grant in Park County, and then up Park CR 60 to its end in the upper watershed of the North Fork of the South Platte. BBS routes have 50 stops along a 24.5 mile route, with 3 minute samples collected at each stop once each year.
-- I ran the Guanella Pass BBS route on June 22 this year, normal timing, with good weather conditions. It was the easiest ever because there were so few birds! The total species I detected was just 29, the lowest ever for the route and down from the 5 year avg of 46 species. The total number of individual birds was just 127, the lowest ever for the route, just 33% of the 5 year avg of 387 individuals. I detected no species at all on10 stops. It is highly unusual to record zero species during a 3 min. BBS sample when weather conditions are reasonable. In fact, barring stops with really loud water noise, I have never had zeros on a BBS stop, but 10 on this survey?!
19 Species that are expected on the route (i.e., found in 3-5 of the last 5 years) were missed entirely. A number of these misses are species which were found in every year in recent history, such as Dusky Flycatcher, Steller's Jay, Red-breasted Nuthatch, Mountain Bluebird, Townesend's Solitaire, Pine Siskin, and Song Sparrow. Of the 29 species found, 15 species were found in numbers 50% or less than the recent 5-year avg. This included all of the species that form the core of the species assemblage of the route except for Warbling Vireo and Wilson's Warbler, which were the only core migrant species in near average numbers this year. Spruce-fir forest and the alpine tundra near the Pass were the habitats that were the most empty of bird song.
** A summary of missed species and those in low numbers is pasted below.
I haven't looked in detail at my other routes, but of the 4 others I've aready run all had notable low counts of many landbirds and more than the normal frequency of "missing" species.
David Suddjian
Ken Caryl Valley
Littleton, CO
| % of | |
| Species | 5 yr avg |
| Broad-tailed Hummingbird | 22% |
| Red-tailed Hawk | Miss |
| Red-naped Sapsucker | Miss |
| Hammond's Flycatcher | Miss |
| Dusky Flycatcher | Miss |
| Cordilleran Flycatcher | 29% |
| Canada Jay | Miss |
| Steller's Jay | Miss |
| Clark's Nutcracker | Miss |
| Common Raven | 22% |
| Violet-green Swallow | 31% |
| Mountain Chickadee | 20% |
| Red-breasted Nuthatch | Miss |
| House Wren | Miss |
| American Dipper | Miss |
| Golden-crowned Kinglet | Miss |
| Ruby-crowned Kinglet | 24% |
| Mountain Bluebird | Miss |
| Townsend's Solitaire | Miss |
| Veery | Miss |
| Swainson's Thrush | Miss |
| Hermit Thrush | 16% |
| American Robin | 50% |
| Pine Grosbeak | Miss |
| Red Crossbill | Miss |
| Pine Siskin | Miss |
| Fox Sparrow | 16% |
| Gray-headed Junco | 36% |
| White-crowned Sparrow | 16% |
| Song Sparrow | Miss |
| Lincoln's Sparrow | 48% |
| Green-tailed Towhee | 42% |
| MacGillivray's Warbler | 50% |
| Audubon's Warbler | 32% |
| Total Species | 64% |
| Total individuals | 33% |
--
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+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/CAGj6RopfakGXBG-VgNhB_KqkxAA5hbrsGSTmOYjqtVreEX3vvg%40mail.gmail.com.
No comments:
Post a Comment