Summary of Spring Migration San Luis Valley

[mvjo...@gmail.com]

I thought I might share my thoughts on the status of the spring bird migration in the San Luis Valley. Summer has arrived and it has been an interesting spring migration. Please realize this is an assessment based on my daily jaunts afield since February's Cranes up to now. I also rely on the 100 San Luis Valley birder's that I network with for their observations. Also, I do peruse eBird and COBIRDS to see what is being seen. I also check our local Doppler radar to get a glimpse of what is passing overhead as we snooze from our busy days. 

The first week of June finds us with a decline in numbers of migrating birds according to the local Doppler Radar for Rio Grande County.  A while back, we had over 200,000 birds passing over Rio Grande County in a single night, but that declined to only 10,000 for last night. Is there a correlation between numbers passing over at night and what you see by day?  I am not so sure. Having been out nearly every day of "spring" from cranes in February to yesterday's tail end of migration, it is really hard to tell. We humans sample such a limited area in our daily jaunts, but I do have some gut feelings on the matter anyway. 

So if I had to assess the SLV migration based on my limited sampling and  what I have seen the past few months, and include all the other data sources, it would probably look like this:

Cranes: Average

Hawks and Raptors: Average

Ducks: Average

Shorebirds: Down

Hummingbirds: Way down

Passerines including Flycatchers, Warblers, Tanagers, Sparrows: Way Down

Numbers of rare birds seen this spring in the SLV by all sources:  About average. Notable species include Brant, Gray Vireo, Yellow-throated Vireo, Red-headed Woodpecker, Neotropic Cormorant, and Grace's Warbler. Likely a few more that I missed. 

I think many of the radar-detected birds simply passed over in the fair weather conditions we had.  There never seemed to be an abundance of birds, both numbers and diversity, in the choice habitats I regularly visited.  Expected numbers of Yellow-rumped Warblers seemed low, and Wilson's and Orange-crowned, pretty much nonexistent.  Where were they? I enjoyed reading the various bird bander reports to see what was happening over the ridge, and the diversity was much greater on the front range than anything here. 

Okay, there you have it. Onto summer! Stay cool!

John Rawinski

Monte Vista, CO