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Diving Activity of Hoary-Headed (Poliocephalus poliocephalus) and Australasian Little (Tachybaptus novaehollandiae) Grebes

2009; The Waterbird Society; Volume: 32; Issue: 1 Linguagem: Inglês

10.1675/063.032.0119

1938-5390

Yan Ropert‐Coudert, Akiko Kato,

Freshwater macroinvertebrate diversity and ecology

In austral spring 2006, a year of severe drought conditions, we timed 314 and 133 dives and subsequent surface durations of Hoary-headed (Poliocephalus poliocephalus) and Australasian Little Grebes (Tachybaptus novaehollandiae), respectively, at a freshwater lake in southern Australia. Hoary-headed Grebes stayed submerged for longer (18.5 ± 3.6 s) than Australasian Little Grebes (15.7 ± 4.2 s and 2.1 ± 1.1, respectively). Consequently, Hoaryheaded Grebes maintained a high and constant diving efficiency (2.33 ± 0.25)—measured as the dive:pause ratio— throughout the study, suggesting that they are better at facing changes in water level of their lacustrine environment than Australasian Little Grebes, which showed an erratic and lower (1.95 ± 0.48) dive efficiency.