Activity and habitat use of waders are influenced by tide, time and weather

Abstract

The influence of tide, time and weather on activity and habitat use of four species of wader were studied at Waikanae Estuary, New Zealand, from late January to late April to assess spatial and temporal segregation among species. Although flock activity was influenced by these abiotic variables in similar ways across all species, movements of active birds around the different habitats available at the Estuary were species dependent. The only species for which abiotic factors consistently influenced the location of resting birds was the Black-winged (Pied) Stilt (Himantopus himantopus leucocephalus). The Double-banded Plover (Banded Dotterel) (Charadrius bicinctus bicinctus) was the only species that regularly fed in drier habitats, whereas the larger species (Black-winged Stilts, Variable Oystercatchers (Haematopus unicolor) and Masked Lapwings (Vanellus miles novaehollandiae)) usually fed in the wetter habitats. Nevertheless, all species displayed some species segregation in habitat use. Overall, the Double-banded Plover and Black-winged Stilt were affected in similar ways by abiotic variables. Time was the most important factor influencing activity and location, followed by wind speed, tide and cloud cover. For the Variable Oystercatcher and Masked Lapwing, tide was the most important factor, followed by either time (Lapwing) or wind speed (Oystercatcher), whereas cloud cover was the least important for both species.