Bird Monitoring and Research: July 20-26, 2012

August 04, 2012 Posted by: Yosemite Bird Researchers and BW – Mather District Volunteer Interpretive Ranger

Period of July 20 - July 26, 2012

Numbers of birds processed are up by nearly 16% this year. This is probably due to a correlation between low snowpack levels and high avian productivity. Yosemite got about 30% of its average snowpack this year which means that bird populations should be having more offspring. We were definitely seeing this in the nets this period where 3 out of every 4 birds processed had hatched this year.  

Interesting birds seen this period included the Black-throated Gray Warbler, Calliope Hummingbird, Green-tailed Towhee, Lesser Goldfinch, Stellar's Jay, and Wilson's Warbler. These birds are rarely found in the researchers' nets. The Calliope Hummingbird, at 3.25 inches in length, is easily the smallest bird that visits Yosemite, beating the Rufous Hummingbird by half an inch. Like many wildflower enthusiasts, the Calliope follows the shift in blooming wildflowers throughout the season. It arrives on the lower slopes in April or May and slowly moves upslope until, by July or August, it is ready to make the journey back south along the highest slopes.  

List of 35 species recorded from July 20-26:

Anna's Hummingbird (Calypte anna)
Calliope Hummingbird (Stellula calliope)
Rufous Hummingbird (Selasphorus rufus)

Red-breasted Sapsucker (Sphyrapicus ruber)
Williamson's Sapsucker (Sphyrapicus thyroideus)
Northern Flicker (Intergrade and Red-shafted) (Colaptes auratus)

Dusky Flycatcher (Empidonax oberholseri)
Pacific-slope Flycatcher (Empidonax difficilis)
Western Wood-pewee (Contopus sordidulus)

Warbling Vireo (Vireo gilvus)

Steller's Jay (Cyanocitta stelleri)

House Wren (Troglodytes aedon)
Pacific Wren (Troglodytes pacificus)

Black-throated Gray Warbler (Dendroica nigrescens)
Hermit Warbler (Dendroica occidentalis)
MacGillivray's Warbler (Oporornis tolmiei)
Nashville Warbler (Vermivora ruficapilla)
Orange-crowned Warbler (Vermivora celata)
Wilson's Warbler (Wilsonia pusilla)
Yellow-rumped Warbler (Audubon's) (Dendroica coronate)

Dark-eyed Junco (Oregon) (Junco hyemalis)
Chipping Sparrow (Spizella passerine)
Lincoln's Sparrow (Melospiza lincolnii)
Song Sparrow (Melospiza melodia)

Green-tailed Towhee (Pipilo chlorurus)

Lesser Goldfinch (Carduelis psaltria)
Pine Siskin (Carduelis pinus)
Purple Finch (Carpodacus purpureus)

Black-headed Grosbeak (Pheucticus melanocephalus)
Bushtit (Psaltriparus minimus)
Red-breasted Nuthatch (Sitta Canadensis)
Brown Creeper (Certhia Americana)
Golden-crowned Kinglet (Regulus satrapa)
Lazuli Bunting (Passerina amoena)
Western Tanager (Piranga ludoviciana)

Table 1. Comparison of Birds Processed during Period 9
(Last Week of July), 2011 to 2012

Station 2011 2012 % change
Big Meadow
74 36 -51.3
Hodgdon (upper)
38 71 +86.8
Hodgdon (lower)
38 63 +65.8
Crane Flat
87 74 -14.9
Gin Flat
36 33 -8.3
White Wolf
16 58 +262.5
Total Recorded
289 335 +15.9


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Last updated: September 4, 2012

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