54 



Birds 



■ Our Liviiii^ Resiiiines 



Table. Regional. natiniKil. and 

 continental population statu;- and 

 trends of selected colonial water- 

 birds in the United States-' as 

 reported by the Breeding Bird 

 Survey. Christmas Bird Counts, 

 and other sources. 



Population status 



BBS/CBC trend'' 



Species 



Region 



Early period 



Recent period % change % +/-routes Years References'^ 



Pelecaniformes 



American white pelican 



Eastern brown pelican 

 Double-crested cormorant 



Continent 



US 

 Canada 

 Mexico 



U.S. 



US 

 Continent 



US 

 Canada 



U.S. 



17,872 nests (1964) 



14,103(1967-69) 



Sporadic (100 nesis) 



7,800-8,300(1970-76) 



22,299 nests (1980-81) 

 53,345(1985-86) 



26.461 ( 



-f5.3" 



■I-3.8'" 

 NA 



■1-6.5'" 

 -t23" 

 +11.5- 

 +8 2- 



+0,6r" 



+0 6r" 



+0.64' 



1966-91 BBS 



1 

 1 

 1 



1966-89 CBC (winter) 

 2 



1966-91 BBS 



1966-89 CBC (winter) 



Ciconliformes 

 Great blue heron 



Great blue tieron 

 Snowy egret 

 Reddish egret 

 Black-crowned night-heron 

 White Ibis 



While-laced ibis 



Wood stork 



Continent 



US 

 Canada 



US 



U.S. 

 US Gull coast 



U.S. 

 Southeast US 



U.S. 

 Western U.S 



U.S. 

 Southeast U.S. 



U.S. 



+1.5" 

 +19 



0.60- 



oer" 



1,700-2,200 pr (1976-78) 1,370-1,900 pr (1989-90) 



40,000-80,000pr(1967-71) 22,000-50,000 pr (1987-93) 



4,500-5,500 pr (1967-75) 13,000-13,500 pr (19851 



2,500-5,200 pr (1976-82) 6,729 pr (1993) 



+0,7 ns 0,54" 



+2,2— 



+2.0" 



+2.8 



+5.0" 



+7.6" 



+1.3 ns 



1966-91 



1966-89 

 1966-89 



1966-89 



1966-89 



1966-89 



1966-89 



BBS 



CBC 

 CBC 

 3,4,5,6 

 CBC 



7 

 CBC 



8 

 CBC 

 9,10 

 CBC 



^Excluding Alaska, Hawaii, and the Pacific coast states. 



''Breeding Bird Survey trends statistically lest for an annual (% change) trend (Hq: trend = 0) and % ol increasing (+) or decreasing (-) routes (Hq no, 

 routes + = no. routes-) Probability levels: 'P<0 10;" P<0,05: "* P<0 01 A lower P value means there is more confidence that the trend is real, A 

 population trend change at the P< 0.10 level is considered statistically significant: ns = not significant Christmas Bird Count trends are conducted similar 

 to annual BBS trend (J R Sauer. NBS. unpublished data). 



^Sources: numbers reler to literature reference number; BBS = Breeding Bird Survey results (J,R. Sauer and B Peterjohn, NBS, personal communica- 

 tion); CBC = Christmas Bird Count trend results (J R Sauer, personal communication), 



1— Evans and Knopf 1993; 2— P Wilkerson, South Carolina Wildlife and Marine Resources Department; 3— Lange, in press; 4— Portnoy 1978; 5— Martin 

 and Lester 1990; 6— Runde 1991; 7— P Frederick, University of Florida, unpublished data; 8— D, Manry, unpublished data; 9— Ogden etal 1987; 10— J. 

 Ogden and M, Coulter, National Park Service, unpublished data; 11— Netlleship and Birkhead 1985: 12— B. Allen, Maine Department of Inland Fisheries 

 and Wildlife, unpublished data; 13— Nisbel, in press; 14— Spendelow and Palton 1988: 15— Erwin 1979; 16— J. Parnell and P. Wilkerson, University of 

 North Carolina and South Carolina Wildlife and Marine Resources Department, unpublished data, 17— Scharf et al, 1992; 18— Blokpoel and Tessier 1993; 

 19— Gochfeld 1983; 20— J,A, Spendelow, NBS, unpublished data; 21— E. Kirsch and J. Sidle, NBS, unpublished data. 



crested cormorant (Phalacrocorax aiiritiis) pop- 

 ulations also declined during the 1940-70 peri- 

 od, probably because of DDT and other pesti- 

 cides; however, this species has increased dra- 

 matically across Canada and the northern 

 United States (Table). In the Great Lakes and 



elsewhere, this species' increases have attracted 

 considerable attention because of the negative 

 effects on fisheries and on the aquaculture 

 industry (Blokpoel and Scharf 1991; Blokpoel 

 and Tessier 1991; Nettleship and Duffy, in 

 press). 



