BBS rte. summary for up in the San Juans (Rio Grande County)

[Marty W]

Greetings CObirders,

I scouted this route on July 1 this year, then did the official survey July 2. The route starts at around 8,400' in rural riparian montane, soon climbs to 9,000'+ riparian forest thru about Stop 15, then quickly climbs further with most of the route being above 10,000' (after Stop 23)--and above 11,000' from Stops 33-50. The whole area above 9,600' or so in the subalpine zone has been devastated by spruce beetle since 2016, and there has been a significant decrease in total numbers of birds for the route (tho NOT of species numbers) in the past 5 years (due to lower numbers of individuals present and breeding in the subalpine). I started the route in 2013. The average total individual count decreased 25% to 360 for the past 4 years, from 480 for the previous 4 years. (This route had "boom" years for both #species and #individuals from 2001-2003, with total individuals going over 500 and into the 600s and species counts reaching 51. Average #species over the past 10 counts is 43, with little variation. But averages for the route are tough to really determine, since there is a lot of missing data/years. For a scattered 10 of the 27 years--including up to 4 consecutive years--since its inception in 1994, no one even did the survey, which suggests there may have been a frequent turnover of observers, which could introduce error into the counts.)

In the subalpine zone since 2016 I've observed decreased #s of Am. 3-toed woodpecker, hermit thrush, robin, junco, Audubon warbler, Clark nutcracker, and chipping sparrow. Further decreases particularly this year occurred in Audubon warbler, pine siskin, and chipping sparrow. But I was thrilled to have three long-eared owl individuals compared to the avg of less than one, an atypical bald eagle, and a probable golden eagle (apparently first for this route--but only on scouting day unfortunately).

Good birding.

Marty Wolf

NW CO Springs