conducted by the DMRP has resulted in guidelines for the development and man- 

 agement of avian habitat (Soots and Landin 1978). Most of the following 

 discussion is taken from the latter report and the reader should consult it 

 for further information, A bibliography is also available (Landin 197Sb). 



There are over 2,0C0 dredged material islands throughout the United 

 States navigational waterways. An estimated 2 million colonial nesting birds, 

 out of a total contiguous United States population of 5 million, nest on 

 dredged material islands (Soots and Landin 1978). For discussions of specific 

 parts of the country see Buckley and McCaffrey (1978), Chaney et al. (1978), 

 Lewis and Lewis (1978), Parnell et al. (1978), Peters et al. (1978), Scharf 

 (1978), Schreiber and Schreiber (1978), and Thompson and Landin (1978). 



Man-made islands vary in their value to colonial nesting birds from crit- 

 ical, e.g., in North Carolina, to relatively unimportant, e.g., along the 

 upper Mississippi River (Soots and Landin 1978). Because of widespread de- 

 struction or premption of natural habitat along the Atlantic and Gulf coasts, 

 dredged material islands are used more extensively than natural sites. Among 

 the species using them, these islands are most important to gull-billed 

 ( Geolqchelidon nilotica ), common (Sterna hirundo ), least (S. a lbifrons ), sand- 

 wich ( Thalasseus sandvicensis ), and royal terns (T. maximus ). 



In many areas, traditional nesting grounds have been destroyed by man or 

 else they are readily accessible to ground predators. Dredged material islands 

 offer relatively good protection from ground predators and disturbances by 

 man. In addition "to use as nesting sites, dredged material islands furnish 

 areas for loafing, feeding, and roosting. Habitat requirements of many species 

 of colonial nesting waterbirds are quite specific and certain dredged material 

 islands often meet the requirements of a particular species. For example, a 

 newly formed, bare ground, dredged material island was used by terns in pre- 

 ference to barrier islands and beaches where predators and human dis^.urbances 

 were more likely to occur (Soots and Landin 1978). 



Factors that determine nesting waterbird use of dredged material islands 

 include: (a) the extent of isolation of the island from ground predators and 

 human disturbance; (b) the habitat diversity found on the island; (c) the sta- 

 bility of the potential nesting substrate; (d) behavioral characteristics of 

 nesting species including social facilitation; and (e) the feeding and forag- 

 ing habitats of the nesting species (availability of nearby feeding areas). 



Soots and Landin (1978) found little difference between the use of a 

 dredged material island and a natural site. The critical factor is the avail- 

 ability of suitable habitat. The habitat may take years to develop through 

 natural plant succession on a dredged material island after its formation or 

 other additional deposition. An island that is isolated from ground predators 

 will probably be used for nesting when it reaches a successional stage attrac- 

 tive to the species. Soots and Parnell (1975) also showed that avifaunal 

 succession on dredged material islands in North Carolina was directly related 

 to the type of vegetation found on the islands. 



Soots and Landin (1978) noted that structure and density of vegetation 

 determined which species of birds would use an island, and rates and patterns 

 of plant succession determined how long an island would be of use to certain 



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