Report of Exploration of Seabird Colonies 235 



eluded on the beat from Grand Isle, but would be more conveniently included 

 with Shell Keys on a distinct route, with Morgan City as headquarters. 



Fourth. The clusters of islands in the shallower parts of the several bays 

 between the Atchafalaya and Mississippi rivers, contrary to expectation, proved 

 almost absolutely unproductive in the present connection. Aside from the fact 

 that all or nearly all of these islands are infested with raccoons, muskrats and 

 other small predaceous mammals, their growths are not especially suited to the 

 nesting of sea-birds; rushes {J uncus), and a low shrub allied to Rhizophora mangle 

 cover most of these islands. In a few cases, however, Spariina and a few other 

 marsh grasses offer suitable nesting-sites for Laughing Gulls, Forster's Terns, 

 and possibly one or two other species; yet only three small colonies of Forster's. 

 Terns were found on such islands. The proximity of fishing camps and the lia- 

 bility of molestation may be responsible for the absence of birds in the majority 

 of such cases. 



The innermost of the islands just referred to are in water so shallow that it 

 was impossible to reach them with the Seabird, which cannot be safely handled 

 in much less than four feet of water; and, while I am confident that almost entirely 

 similar conditions prevail throughout these districts of clustered marsh islands, 

 a very shallow-draft boat, working among the innermost of the islands, might 

 discover a few additional colonies of Forster's Terns. The territory uncovered 

 by the Seabird from the outside could easily be covered in a week or ten days, 

 at ihe most by a small boat working from the actual mainland. 



NESTING COLONIES 



1. Shell Keys (Now a reservation). — These keys lie about south of east from 

 Southwest Pass, Vermilion Bay, and are about four miles south of the mouth of 

 Oyster Bayou, Marsh Island. The keys form a reef about a mile and a half in 

 length. The eastern key is the longest and is separated by about a half-mile 

 from the others. The chart shows the reef as composed of a single key. 



These keys were visited May 16 and 17. About 300 Brown Pelicans, 500^ 

 Man-o'-War Birds and 900 Royal Terns were seen on the keys. The Terns had 

 begun to nest on the central key and about 200 nests were found there. About 

 15 Pelican nests were found on this key and about 20 nests on the western key. 

 The Man-o'-War Birds, so far as known, use the keys only as a resting-place. 



Besides the birds seen on Shell Keys, about 60 Brown Pelicans and 200 Royal 

 Terns were seen on Diamond Reef Keys, two and one-half miles off shore from 

 Cheniere la Croix, Marsh Island. These latter keys are merely resting-places. 



The Shell Keys are composed entirely of oyster-shell fragments, are devoid 

 of vegetation, have an average breadth of about 15 feet, and are nowhere more 

 than three or four feet above ordinary high tide. 



2. Caroline Cut Island. — This small island is a portion of Isle Derniere. 

 It is not named separately on the government charts. It lies west of a pass known, 

 locally as Caroline's Cut. 



