Clearing and draining of bottomland forests for 

 agricultural purposes has reduced the abundance of 

 traditional white-tailed deer habitat. In some areas free- 

 ranging livestock compete with deer for food and space 

 (McM^an 1966). Saltwater intrusion into fresh 

 marshes from dredging operations may reduce 

 preferred food types of white-tailed deer. In coastal 

 areas, illegal hunting, reduced cover, and free-ranging 

 dogs sometimes limit the abundance of deer (Chabreck, 

 R. H., pers. comm., December 1977, Louisiana State 

 University, School of Forestry and Wildlife Manage- 

 ment, Baton Rouge). 



5.3 BIRDS 



5.3.1 AMERICAN WHITE PELICAN {Pelecanus 

 erythrorhynchos) 



The American white pelican is a common winter 

 resident of the Chenier Plain as well as of the entire 

 Gulf coast. Largest numbers are present from October 

 to AprO, but flocks of up to 1000 may be present 

 along the coast in summer (Lowery 1974a). Nesting 

 has not been confirmed in Louisiana, but there have 

 been some recent unconfirmed nesting sites reported. 

 Some scattered nesting occurs in southern Texas 

 (Lowery 1974a, Palmer 1962). 



In the Chenier Plain area, daUy movements largely 

 consist of fliglits from resting areas to nearby feeding 

 areas. Feeding occurs largely in the early morning and 

 late evening, especially during the incoming tide 

 (Palmer 1962). 



Pelicans rest and feed largely in shallow open 

 waters such as lakes and fresh water impoundments, or 

 in coastal bays and inlets (Imhof 1976, Pahner 1962). 

 Flocks may feed occasionally in salt or brackish 

 marshes. They often rest on beaches and sandbars 

 (Palmer 1962). Pelicans usually feed simultaneously in 

 a tight flock. The flock often encircles a school of fish 

 and herds it into shallow water where they are easily 

 caught. Imhof (1976) reports that Gulf menhaden, a 

 commercially important species, comprised 90% of the 

 diet of white pelicans along the Gulf coast. 



The American white pelican nests primarily in the 

 northwestern United States and southwestern Canada. 

 Great Salt Lake in Utah and Pyramid Lake in Nevada 

 are two well-known nesting areas. They breed on rela- 

 tively bare islands that are remote from man's activities 

 (Palmer 1962). 



White pelican numbers are apparently decreasing 

 because of the loss of suitable nesting habitat and their 

 intolerance to human disturbances. Individuals are 

 sometimes killed by hunters and fishermen (Palmer 

 1962). White pelican colonies often break up during 

 severe weather (Hildebrand and Blacklock 1969). 



1962, Oberholser 1974). It currently breeds in the 

 Chenier Plain, as has the double-crested cormorant 

 {Phalacrocorax auritus) a rare winter resident (Lowery 

 1974). The olivaceous cormorant is a bird of fresh 

 and brackish water habitats (Palmer 1962). The species 

 does not occur where suitable perching sites do not 

 exist (Morrison and Slack 1977). In Louisiana, the 

 olivaceous cormorant is found almost exclusively in the 

 Chenier Plain. Eight colonies have been reported for 

 southwest Louisiana (Portnoy 1977). Seven of these, 

 representing 99.5% of the birds, were in the Chenier 

 Plain. 



Cormorants feed under water, almost entirely on 

 fish (Palmer 1962). They often feed in flocks and 

 individuals work in unison to herd fish into compact 

 schools. Sometimes thousands of birds gather where 

 food is plentiful. In addition to fish, cormorants feed 

 on frogs, tadpoles, and dragonfly nymphs (Oberholser 

 1974). In the Chenier Plain, social feeding, apparently 

 on schools of small fish, has often been observed 

 (Hamilton, R., pers. comm., School of Wildlife and 

 Forestry, Louisiana State University, Baton Rouge). 



Olivaceous cormorants commonly nest in the 

 tallest trees or shrubs in fresh or brackish marshes or in 

 swamp forests, often mixed with colonies of herons, 

 egrets, ibises, or spoonbills (Portnoy 1977). All 

 cormorant colonies reported for the Chenier Plain were 

 in fresh-water habitats (Portnoy 1977). Two of these 

 were located in swamps, two on spoil banks, and three 

 in marshes. Trees were used for nesting in two colonies 

 and woody shrubs were used in the other five. In the 

 Chenier Plain, most nesting occurs from AprO to June 

 (Palmer 1962, Portnoy 1977). Nests are constructed in 

 living or dead branches 1 to 7 m (3 to 23 ft) above 

 water, or on bare ground if woody sites are lacking. 

 Both sexes feed the young 3 to 8 times daily. Boat- 

 tailed grackle and raccoon are major predators of eggs 

 and young (Palmer 1962). 



Cormorants occur largely where fish are abundant. 

 They are not tolerant of extensive human interference 

 (Palmer 1962). Numbers have fluctuated in Texas since 

 1945. A population crash in the 1960'smay have been 

 related to low reproductive success caused by high 

 levels of pesticide and polychlorinated biphenyl (PCB) 

 residues in adults. Olivaceous cormorants are now 

 increasing in numbers in Texas and southwestern 

 Louisiana, as the levels of residues decrease. Other fish- 

 eating birds in Texas showed similar population 

 changes in association with residual pesticide levels 

 (Morrison and Slack 1977). Habitat loss has also caused 

 a significant decline in numbers of olivaceous cormo- 

 rants (Morrison and Slack 1977, Oberholser 1974). 

 Part of the recent increase in numbers of breeding 

 cormorants is due to establislmient of several Audubon 

 Society refuges. 



5.3.2 OLIVACEOUS CORMORANT 



{Phalacrocorax olivaceus) 



The olivaceous cormorant is a permanent resident 

 in the Chenier Plain, which is the northernmost part of 

 its range. In the United States, it is native only in 

 coastal Texas and southwestern Louisiana (Palmer 



5.3.3 GREAT BLUE HERON (Ardea herodias) 



The great blue heron is a relatively uncommon 

 permanent resident of the Chenier Plain. Post-nesting 

 dispersal is common (Byrd 1978). Daily movements 

 consist of flights between nesting or roosting sites and 

 feeding areas. 



231 



