Our Liviii}^ Rtwdiiivcs — Tlw Giviit Plains 



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declines during the last 26 years. Population 

 declines of four species (mountain plover 

 [CliarciJriiis montaniis]. Franklin's gull [Lcmis 

 pipixcaii]. Cassin's sparrow [Aiwophila 

 cassinii]. and lark hunting [Calamospiza 

 mekmocorys]) are statistically significant. 



Similarly. 14 of the 20 more widespread 

 species that evolved primarily on the Great 

 Plains declined during this period, with the 

 declines in the eastern meadowlark (Sturuclhi 

 magna) and 5 sparrows (grasshopper 

 [Aminod ramus savanmirum], Henslow's [A. 

 henslowii], lark [Chondestes grammacus]. 

 Brewer's [Spizella hreweri], and clay-colored 

 [S. pallida]) being statistically significant. 

 Across all grassland species, populations of 

 only the upland sandpiper (Bartramia longicaii- 

 da) and McCown's longspur {Calcariiis 

 mccownii) have increased significantly since 

 1966. 



Patterns of Bird Declines 



Reasons for population declines among 

 species within the grassland avifauna are diffi- 

 cult to assess. Through examining trends for 

 those species where declines are supported sta- 

 tistically, the declines appear to be localized for 

 Franklin's gull, dickcissel, Henslow's and 

 grasshopper sparrows, lark bunting, and eastern 

 meadowlark; these species show a significant 

 difference in the proportion of surveys with 

 increasing versus decreasing populations. This 

 pattern of significant local declines for species 

 that also are declining continentally reflects a 

 pattern of loss of local breeding habitats. 



Declines in populations of mountain plover 

 and Cassin's and clay-colored sparrows were 

 universal across their respective geographic 

 ranges. The seasonal distributions and ecology 

 of these spaiTows are poorly understood. The 

 plover is now rare on its former wintering areas 

 in southern Te,\as and has a fragmented winter- 

 ing distribution in California. Ongoing research 

 on plovers indicates that declines of these 

 species may be attributable to decline or degra- 

 dation in the quality of habitats available for 

 wintering. 



Population trends for a third group of grass- 

 land species (feiTuginous hawk [Buteo regal is]; 

 Mississippi kite [Ictinia mississippiensis]; 

 upland sandpiper; short-eared owl [Asia flam- 

 meiis]: horned lark [Eremophila alpestris]: 

 western meadowlark [Sturnella neglecta]: and 

 vesper [Pooeceles gramineiis], savannah 

 [Passerculus saiidwichensis]. and Henslow's 

 sparrows) show significant changes in relative 

 abundance among surveys, even though conti- 

 nental numbers are stable. The geographic dis- 

 tributions of these species appear to be chang- 

 ing at present. 



Table. .Aiiiuial rales of change in 

 continental pnpiilations of endem- 

 ic gra,sslan(J hi id species, 1966-91 

 (Breeding Bird Survey data). 



^Percentages totaling <100°o include some routes with no change in 

 numbers of birds detected Astensk indicates significant differences (P< 

 05) between number of sun/eys with increasing versus decreasing 

 species populations 



''Annual rate (expressed as a percentage) of change in population num- 

 bers. Asterisk indicates a statistically significant (P< 05) rate of popula- 

 tion change 



Although species associated with wetlands 

 have certainly declined since settlement of the 

 grasslands in the mid-1800"s. Breeding Bird 

 Survey data indicate that populations of the 

 endemic marbled godwit and Wilson's 

 phalarope are stable. Wetland conservation 

 actions to benefit waterfowl have apparently 

 stabilized populations of these two species. 



Are There Fewer Birds on the Great Plains? 



Many species of forest birds historically 

 occurred west of their eastern deciduous forest 

 habitats in streamside vegetation of the eastern 

 Great Plains. As most endemic grassland birds 

 have declined, they have been replaced locally 

 by eastern species moving into windbreaks and 

 developing riparian forests along streambeds of 

 the short-grass prairie. The streamside forests 

 evolved with water management practices in the 

 west and have favored the movement of many 

 species farther onto and across the grasslands. 



