Productivity and Chick Growth Rates of Royal Tern (Thalasseus maximus) and Sandwich Tern (Thalasseus sandvicensis) on the Isles Dernieres Barrier Island Refuge, Louisiana

Abstract

Abstract. Barrier islands in Louisiana and elsewhere in the northern Gulf of Mexico region provide valuable breeding habitat for numerous waterbird species; however, these islands are also deteriorating at an alarming rate. Management and conservation of waterbird species in these dynamic environments require a better understanding of the breeding biology for northern Gulf of Mexico populations. Productivity parameters were investigated for Royal (Thalasseus maximus) and Sandwich (T. sandvicensis) terns at the Isles Dernieres Barrier Island Refuge in Terrebonne Parish, Louisiana, during the 2009 and 2010 breeding seasons. Mean hatching success for Royal Tern was 77% (n = 169 nests), while Sandwich Tern hatching success was 75% (n = 130 nests). For both Royal and Sandwich terns, the estimated probability that a chick survived from hatching to fledging age was 55% (n = 630 nestlings). Overall, estimated breeding success for Royal and Sandwich terns was 42.3% and 41%, respectively. Chick growth rates were si...