Effects of Disturbance on Activity and Energy Budgets of Migrating Waterbirds in South-Central Oklahoma

Abstract

We studied effects of disturbance on migrating waterbirds during spring on Cumberland Pool at Tishomingo National Wildlife Refuge, Tishomingo, Oklahoma, USA, 1999 and 2000. We recorded 240 disturbances in 477.5 hr of observation of American coots (Fulica americana), American white pelicans (Pelecanus erythrarhynchos), black terns (Chlidonias niger), blue-winged teal (Anas discors), and Franklin's gulls (Larus pipixcan). Recreation (n = 208) accounted for 86.7% of all disturbances, natural disturbances (n = 23) accounted for 9.6%, and 3.3% of disturbances (n = 8) were unknown. Boat fishing increased alertness by American white pelicans but did not affect escape behavior. Recreational disturbances caused increases in escape activities and alertness of American coots. However, only boat fishing increased energy expenditure by American coots. Rates of disturbance differed between species and appeared to be correlated to foraging strategies, habitat requirements, and type of disturbance. Therefore, managers of public lands should consider habits and migration chronologies of waterbirds when setting seasonal recreation dates. Modifying recreation policy could reduce rates of disturbance to some waterbirds. Future research should be aimed at constructing energy budgets and measuring body condition of birds at multiple staging areas during spring to determine whether recreational disturbance ultimately affects reproductive success.