Breeding Bird Survey Results 2015

Stoller-ESER-198
EXECUTIVE SUMMARY

Breeding bird surveys (BBSs) have been conducted annually since 1985 (no surveys were conducted in 1992 and 1993) to monitor bird populations on the Idaho National Laboratory (INL) Site. In 2015, we conducted surveys from May 29 to June 30 along 13 established routes, five of which are part of a nationwide survey administered by the U.S. Geological Survey (USGS) and eight of which border INL Site facilities. We documented 3,503 birds from 52 species during those surveys. Bird abundance was less than the 1985-2014 average of 4,748 birds, and the number of species (i.e., species richness) was lower than the 28-year average of 56.

 

Compared with past surveys, we observed similar patterns of bird abundance among those species that are typically the most numerous. In 2015, the six species that were documented in greatest abundance were horned lark (Eremophila alpestris, n = 897), western meadowlark (Sturnella neglecta, n = 667), sage thrasher (Oreoscoptes montanus, n = 499), mourning dove (Zenaida macroura, n = 296), sagebrush sparrow (Artemisiospiza nevadensis, n = 227), and Brewer’s sparrow (Spizella breweri, n = 154). With the exception of the mourning dove, these species have been the five most abundant 23 times during the past 29 years of surveys, and in the remaining six years they were among the six most abundant species.

 

Investigators observed two species that were previously not recorded during the INL surveys: one unidentified hummingbird and one peregrine falcon (Falco peregrinus). Additionally, we observed a great blue heron (Ardea herodias), which had been recorded in 2 of the past 28 years.


Species observed during the 2015 BBS that are considered by the Idaho Department of Fish and Game as species of conservation concern included the Franklin’s gull (Larus pipixcan, n = 76), grasshopper sparrow (Ammodramus savannarum, n = 6), ferruginous hawk (Buteo regalis, n = 15), long-billed curlew (Numenius americanus, n = 7), peregrine falcon (Falco peregrinus, n = 1), greater sage-grouse (Centrocercus urophasianus, n = 1), and burrowing owl (Athene cunicularia, n = 1).

 

We noted two negative trends regarding sagebrush specialist species. Brewer’s sparrow and sagebrush sparrow (both specialists) have been at historically low levels since 2011. We attribute this decline to the loss of sagebrush habitats during large fires in 2010 and 2011. Conversely, the common raven, which preys on sage-grouse eggs (another sagebrush specialist), continues to trend upward and was observed in 2015 at higher levels than in any other INL Site breeding bird survey, except 2010.


Full 2015 Breeding Bird Survey Report (pdf format)