BOTH C (2013) Unusual polygyny in Pied Flycatcher Ficedula hypoleuca: two females in one nest. LIMOSA 86 (4): 217-221.

Pied flycatchers are known to be polygynous, with males having two females breeding in separate nest boxes. In our study population in SW-Drenthe (NL) 4% of males exhibit the normal pattern of polyterritorial polygyny (Table 2), but in 2012 I found an unusual case with two females sharing the same nest box and successfully raising a shared brood. A reconstruction shows that the first female started laying in this nest box on 3 May, but a new nest was built on top when five eggs had been laid. This female resumed laying three days later, and the second female started again four days later, six days after her arrival (Table 1). In total ten eggs were laid, which hatched highly asynchronously. Probably as a result, four chicks died, but the remaining six were fed by all three parents and fledged in good condition.

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