Jamaica Bay studies. II. Effect of tidal, temporal and weather variables on distribution of ibises, egrets and herons on a coastal estuary.

Although great blue herons Ardea herodias were most abundant on tidal areas, other species were most abundant on the freshwater ponds. The most important variable influencing the number of flocks and birds for all areas was stage in the tide cycle. In general, they fed on the bay at low tide and during rising tides, and fed in the ponds at high tides. Secondly, wind velocity and direction had a significant influence on abundance and distribution; birds avoided the bay on strong, westerly winds and moved into the protected ponds. Snowy egret Egretta thula abundance and distribution was influenced more by wind variables than were numbers of glossy ibis Plegadis falcinellus, attributed to feeding methods: snowy egrets are visual foragers whose success depends on being able to see prey whereas ibis are tactile foragers. -from Author