56 



Birds — 6*///" Living Re.soiirccs 



(Nisbet. in press): BBS and CBC data do not 

 show any change (Table). Changes in landfill 

 practices that have reduced food supplies along 

 the northeastern coast may have reduced winter 

 survival and slowed the population growth of 

 this species. In the Great Lakes, however, her- 

 ring gulls have shown a dramatic increase since 

 the^late 1970"s. 



Ring-billed gulls (L. JcUnvarenis) continue 

 to increase across the northern tier of states. 

 Canada, and the Great Lakes (Blokpoel and 

 Scharf 1991: Blokpoel and Tessier 1991; 

 Table). The BBS and CBC data suggest signifi- 

 cant increases in the LInited States and Canada 

 (Table). Refuge and resource managers are con- 

 cerned over the reported decline in the 

 Franklin's gull it. pipixcaii). an interior, marsh- 

 nesting species that may be vulnerable to agri- 

 cultural pesticides (White and Kolbe 1985). The 

 BBS trends indicate that the numbers of this 

 species significantly declined in the United 

 States from 1966 to 1991. However, adding 

 1992 and 1993 data indicates a nonsignificant 

 decline in the United States, which raises the 

 question of the value of BBS data for this tlock- 

 feeding species (J.R. Sauer. personal communi- 

 cation). 



Gull-billed terns (Sterna lulullca] are a 

 species of special concern to many coastal 

 states and were on the fomier (1987) USFWS 

 management list. Recent population figures 

 from Texas (Lange. in press). Louisiana (Martin 

 and Lester 1990). and the mid- Atlantic region 

 (Virginia to South Carolina) suggest that the 

 population is reasonably stable over the long 

 term but en'atic from year to year (Table). 



The Forster's tem (S. forsteri) nests both 

 along coasts and across the interior of the north- 

 ern tier of states and Canadian provinces. State 

 surveys do not suggest declines in most states 

 from New Jersey (CD. Jenkins. New Jersey 

 Division of Fish. Game and Wildlife, personal 

 communication) to Virginia (Erwin 1979). Data 

 are insufficient in the Great Lakes to assess 

 trends. The trends from the BBS and CBC are 

 contradictory, with breeding trends indicating 

 declines and wintering trends a significant 

 increase. This species is en"atic in its nesting 

 and probably not sampled well by either of 

 these surveys. 



Common terns (S. luniiulo). while abundant 

 and increasing along the U.S. northeastern coast 

 (Buckley and Buckley 1984), are considered 

 endangered, threatened, or a species of special 

 concern in six Great Lakes states and Ontario 

 (Blokpoel and Schaif 1991; Scharf et al. 1992). 

 Even though tern numbers increased from 1977 

 to 1989 in the U.S. Great Lakes (Table), the 

 number of their colony sites has declined from 

 31 to 23. Competition with the ring-billed gull 

 is a major factor in this decline (Schaif et al. 



1992). 



The roseate tern (5. doiii^allii) is an endan- 

 gered species (since 1987) and breeds in two 

 populations in the western Atlantic. The west- 

 ern North Atlantic population includes the mar- 

 itime provinces south to Long Island. New York 

 (with a few possibly from New Jersey to 

 Georgia); the U.S. Neotropical population is 

 confined to Puerto Rico, the Virgin Islands, and 

 southern Florida. In the northern population, the 

 number of breeding pairs ranged from 2.855 to 

 3.285 pairs during the 1976-80 period 

 (Gochfeld 1983) to 3.200 estimated pairs in 

 1993 (J. Spendelow. National Biological 

 Service, personal communication: Table; 

 Figure). In the southern U.S. population, pair 

 estimates from the 1976-79 period range from 

 about 1.900 (Gochfeld 1983) to about 2.600 

 pairs in the Florida Keys. Puerto Rico, and the 

 Virgin Islands (Blokpoel and Tessier 1993; 

 Table). Earlier records are sparse in this region, 

 making trends difficult to determine. 



The least tem iS. aittilUiniin) is di\ided into 

 three subspecies in the United States and 

 Canada: the interior {S.a. athalassos) and 

 California {S.a. hwwni) subspecies are listed as 

 endangered. In the Mississippi River drainages, 

 the interior least tern seems to have increased 

 from the 1986-87 period to 1991 (E. Kirsch and 

 J. Sidle. NBS. unpublished data; Table: Figure). 

 The 1993 fioods probably prevented recent 

 nesting in many river stretches. 



The black tem (Clilidoiila.s iiiger) is listed as 

 either endangered or a species of concern in 

 many northern states, including New York. 

 Iowa. Illinois. Wisconsin. Ohio, and Indiana. Its 

 population has decreased at the BBS continen- 

 tal and U.S. levels from 1966 to 1992 (Table; 

 Figure). From 1982 to I99I. BBS data indicate 

 a significant increase in Canada with continued 

 decrease in the United States. This suggests a 

 species" displacement to the north, possibly a 

 result of changes in wetland conditions in the 

 northern tier of the United States. A confound- 

 ing factor may also be that the Canadian surveys 

 have been more intensive for this species in 

 recent years. 



References 



Bildstein. K.L. 1993. White ibis: wetland wanderer. 

 Smithsonian Institution Press, Washington. DC. 242 pp. 



Blokpoel. H.. and W.C. Scharf. 1991. Status and conser\a- 

 tion of seabirds nesting in the Great Lakes of North 

 America. Pages 17-41 in J. Croxall, ed. Status and con- 

 servation of the world's seabirds. International Council 

 for Bird Preservation. Cambridge. England. 



Blokpoel. H., and G.D. Tessier 1991. Distnbution and 

 abundance of colonial waterbirds nesting in the Canadian 

 portions of the lower Great Lakes system in 1990. 

 Canadian Wildlife Ser\'ice Tech. Rep. Series 117. 16 pp. 



Blokpoel. H.. and G.D. Tessier. 1993. Atlas of colonial 

 waterbirds nesting on the Canadian Great Lakes. 1989- 

 1991. Part 1. Cormorants, gulls, and island-nesting terns 



