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The authors discuss the study by G. A. Rebstock and P. D. Boersma which explores the variation in the temperature and egg incubation period within clutches of the Magellanic Penguin (Spheniscus magellanicus). Authors of the study include the period before the delayed onset of incubation that leads to confusion. The authors argue that the conclusions of the study are based on an unconventional definition of incubation period.

The article discusses a study which examined the natural and human influences that affect incubation patterns and sex role in Black Oystercatcher (Haematopus bachmani) in Alaska. Researchers used 24-hour-per-day video monitoring of breeding pairs to examine incubation patterns. The study found that female and male shorebirds have different but complementary incubation patterns, which facilitates an efficient egg care, and are affected by disturbance and nest predation threats.

The article presents a study concerning parental behavior controls during incubation stage and asynchrony of hatching in Magellanic Penguins. It states that two eggs were tested whether its temperatures differ and the delayed onset of incubation affects the pattern. Moreover, it notes that parental incubation behavior define why the incubation period of second eggs was shorter that of first eggs.

In environments such as arctic tundra, where bird densities are low and habitats are comparatively homogeneous, suitable nest sites likely are not limited. Under these conditions, reproductive success of birds may be determined by factors other than the habitat characteristics of nest sites. We studied the relative influence of nest habitat, food, nest distribution, and parental behavior on the reproductive success of tundra- breeding shorebirds at East Bay, Southampton Island, Nunavut, Canada. From 2000 to 2002, we monitored the nests of five species: Black-bellied Plover (Pluvialis squatarola), Semipalmated Plover (Charadrius semipalmatus), Ruddy Turnstone (Arenaria interpres), White-rumped Sandpiper (calidris fuscicollis), and Red Phalarope (Phalaropus fulicarius). For each species, habitat differed between nest sites and random sites. In contrast, habitat differed between successful and failed nest sites only for White-rumped Sandpipers. Shorebirds did not prefer to nest in habitats where food was most abundant. Although nest success varied among species in all years, artificial nest experiments suggested that interspecific variation in predation rate was not related to habitat type. Instead, the marked interspecific variation in nest success may have been related to incubation behavior. Species taking fewer incubation recesses had higher nest success, although these results should be viewed as preliminary. The factor with the greatest interannual influence on nest success was fluctuating predation pressure, apparently related to the abundance of predators and lemmings. [ABSTRACT FROM AUTHOR]