Sheng-Feng Shen

© S.F. Shen

Tussling during egg laying

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We discovered the tussling behavior during the 2004 season. It is possible that the alpha female arrives at the nest earlier (6/8 cases in 2004 season) and prevents the beta female from getting into the nest to lay eggs. However, it is not clear why females only lay eggs during this short period of time and engage in such tussles with other females.

Egg tossing

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Yuhina Clips

Egg tossing was first observed in yuhinas during our 2004 season. It is therefore

possible that dominants actively toss other females’ eggs so that they can increase their share.

Perch weighting system & feeding

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We set up a perch-weighing system near the entrance of the yuhina nest in order to measure the co-breeders’ body conditions.  Note that nestlings are individually marked on the bills. The perch that the bird stands on is connected to a load cell sensor.