Our Livinf; Rt'iouive.s — Binl\ 



55 



Ciconiiformes 



Heron, egret, and ibis nesting colonies were 

 reduced along much of the U.S. coastline in the 

 early 1900"s as a result of the millinery trade; 

 however, the species have all recovered their 

 former ranges. Great blue herons are the most 

 abundant and ubiquitous of the wading birds in 

 North America: all indications suggest that their 

 populations have increased, especially in the 

 United States (Butler 1992; Table). One reason 

 for this trend may be that winter survival has 

 increased as herons feed heavily at aquaculture 

 facilities in the southern United States. 



The reddish egret (Egretta rufescens) is list- 

 ed as a species of management concern to the 

 USFWS (OMBM 1994).^It nests in small num- 

 bers along the gulf coast and in southern Florida 

 (Table). Reddish egrets seem to have declined 

 some in Texas (Lange. in press) and Louisiana 

 (Portnoy 1978; Martin and Lester 1990; 

 Figure), but the data are not adequate in Florida 

 to assess trends. 



Snowy egrets (E. lliiila) were prized by 

 plume traders at the turn of the century, and the 

 species suffered dramatic population declines; 

 however, by the 1970"s these egrets had recov- 

 ered their former range. More recently, their 

 populations declined in some Atlantic regions 

 such as Virginia (Williams et al. 1990) and 

 southern Florida (Robertson and Kushlan 1974; 

 Ogden 1978; Table). 



The black-crowned night-heron {Nycticorax 

 nycticorax), which occurs across all of North 

 America, may be declining in pails of Canada, 

 south to Texas (Davis 1993) and perhaps 

 Virginia (Williams et al. 1990; Table). 



Ibises are more nomadic in their breeding 

 distribution than are other wading birds. White 

 ibis (Endocimus albiis) have declined markedly 

 in southern Florida as a result of hydrologic 

 changes in the Everglades (Robertson and 

 Kushlan 1974; Ogden^ 1978). Their breeding 

 distribution has shifted northward, and large 

 colonies exist in Georgia and the Carolinas 

 (Ogden 1978; Bildstein"l993). Over the entire 

 southeastern United States the species may not 

 have undergone major changes, although state 

 estimates have been enatic (twofold changes in 

 2-3 years; Table). 



The white-faced ibis {Plciicidis chilli) was 

 formerly (1987) on the USFWS management 

 concern list, but is not on the 1994 national list 

 (OMBM 1994). Population data for the central 

 and western populations (noncoastal) indicate a 

 marked increase in the numbers of these ibis 

 from the early 1970's to 1985 (D. Manry, per- 

 sonal communication; Table). 



Wood storks (Mycteria americcma). which 

 have been federally listed as endangered since 

 1984, nest from Florida north to South Carolina 



in the United States, in Cuba, and in enormous 

 numbers in the river deltas of eastern Mexico, 

 especially the Usumacinta-Grijalva Delta. Stork 

 colonies have shifted north from the Everglades 

 to central and northern Florida. Georgia, and 

 South Carolina since the 1970"s (Robertson and 

 Kushlan 1974; Ogden 1978; Ogden et al. 1987). 

 Recent inventories of nesting populations in the 

 United States indicate a modest increase in 

 numbers over the past 10-15 years (Table; 

 Figure). 



Because of the mobility of wood storks and 

 ibis, monitoring them requires a regional 

 approach to ensure standardization in survey 

 timing and methods. Individual state inventories 

 are inadequate to address many highly mobile 

 species. 



Charadriiformes 



This order of colonial-nesting waterbirds 

 includes the alcids (murres, puffins, auks), 

 shorebirds, gulls, terns, and black skimmers 

 {Ryiichops niger). Although some species of 

 alcids and terns were nearly extirpated by 

 hunters or millinery traders during the early 

 19()()"s. they rebounded well in many areas. 



Alcid populations are rare in the eastern 

 United States. In maritime Canada, however, 

 alcid numbers are substantial (Nettleship and 

 Birkhead 1985; Erskine 1992), though there is 

 concern over Canada's razorbill (Alca tarda) 

 populations, which declined by more than 75% 

 from 1960 to 1982 (Nettleship and Birkhead 

 1985). These declines may be the result of con- 

 flicts with commercial fisheries. 



Canadian populations of Atlantic puffins 

 (Eratercula arctica) have declined a great deal 

 in some areas. The largest Atlantic puffin 

 colony in North America is at Witless Bay, 

 Newfoundland (61% of continental breeding 

 total); this colony has declined by 25%-35% 

 from 1973 to 1980 (Nettleship and Birkhead 

 1985). Again, competition between birds and 

 commercial fisheries (capelin) may be causing 

 much of the decline. In Maine, a successful 

 transplant program has been in effect for more 

 than a decade to reintroduce nesting Atlantic 

 puffins onto several coastal islands (Kress and 

 Nettleship 1988); numbers remain small, how- 

 ever (Table). 



Gull populations have increased substantial- 

 ly from the middle part of the century to the pre- 

 sent (Buckley and Buckley 1984; Nisbet, in 

 press). Great black-backed gulls {Lxirus mari- 

 mts) have increased in some mid- Atlantic states 

 but have probably declined in Maine (Nisbet, in 

 press; Table). Herring gull populations probably 

 peaked around 1980 at about 1 lO.OtJO pairs 

 along the northeastern U.S. coastline, but popu- 

 lations may have declined during the 1980"s 



^- endangered 

 Wood stork 



I of concern 



4-- 



76-82 



93 

 Roseate tern, North 

 Atlantic population 



^30 



I ■_ 



B^S ■ 



mm 



20 ^'^T^ 



76-80 



Interior least tern 



93 



65- 



55- 



o 45- 



35- 



86-87 



20- 



P^ Reddisli egret 



S 15 



±^ 



76-78 



89-90 



Black tern 



■%v. 



■ii^ltal 



66 71 76 81 86 91 

 Year 



Figure. Trends of selected colo- 

 nial waterbirds either endangered 

 or on the U.S. Fish and Wildlife 

 Service's list of species of man- 

 agement concern in the lower 48 

 states (excluding the Pacific coa.st). 

 Black tern trends are count indices 

 from the Breeding Bird Survey 

 ( mean or average number of birds 

 per route). Lighter color shows 

 range of variation in estimates. 



