<br />"'"
<br />!'... Table 4
<br />:,,1") Marsh and Water Bird Use-Days on
<br />'.....; Monte Vista and Alamosa National Wildlife Refuges (NWR )
<br />-
<br />'. ,)
<br />~",:> Monte Vista NWR Y Alamosa NWR 3./
<br /> Species 1979 1980 1979 1980
<br /> Pied-billed gre bell 3,356 1,863 3,175 1,650
<br /> White-faced ibis 3,550 2,050 4,720 3,150
<br /> American bitter~/ 3,190 3,600 2,520 3,950
<br /> Snowy egret1./ 650 520 9,250 2,100
<br /> Black-crowned night heron1./ 1,650 4,500 5,200 7,600
<br /> Virginia rai1.Y 4,000 4,000 1,800 900
<br /> Great blue hero~/ 750 570 3,772 2,970
<br /> Greater sandhill cran~/ 388,150 509,100 40,800 53,100
<br />,Whooping cran~/ 217 406 65 119
<br /> Eared grebe 360
<br /> Western greb~/ 20 160 80
<br /> White pelican 18
<br /> Horned grebe 1,350 120
<br /> Green heron 1,020 960
<br /> Sora rail 1,000 1,000
<br /> Common egret 10
<br /> Total 405,513 527,007 74,832 77 ,949
<br /> Use-days/acre 31.5 40.9 8.3 8.6
<br /> Use-days/acre average 36.2 8.4
<br />
<br />l/ Total acreage for Monte Vista NWR not including areas of crops, roads, and
<br />buildings is 12,876 acres.
<br />l/ Total acreage for Alamosa NWR not including areas of crops, roads, buildings,
<br />and Hansen Bluff is 10,357 acres.
<br />3/ Breeders.
<br />!/ Migratory birds of high Federal interest.
<br />
<br />During 1979-80, use by these three groups of species averaged 64.8 use-days/acre/
<br />season at Monte Vista NWR. Aerial transects flown by the BR in 1978 indicated
<br />significantly higher concentrations of water birds using wetlands outside
<br />Alamosa NWR (which had an 1979-1980 average of 35.1 use-days/acre/season).
<br />Because the aerial transects were designed to reveal rough estimates of dif-
<br />ferential habitat use and not intended to produce population estimates, those
<br />transects cannot be used to estimate shorebird use-days for the Closed Basin
<br />project area. However, the transect data and knowledge of shorebird habitat
<br />preference suggest that Closed Basin project area supports higher
<br />use-days/acre/season of wetland than does Alamosa NWR. For the three groups of
<br />
<br />7
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