VAN NOORDEN, B (2020) Runt egg of Icterine Warbler Hippolais icterina. LIMOSA 93 (3): 142-145.

On 30 June 2015 a runt egg was discovered in a clutch of four of an Icterine Warbler in the Peel region, southern Netherlands. It was the first record of a runt egg in a field study that covers 19 years and where 2833 normal eggs where found. The egg measured 14.4 x 10.9 mm and had a calculated volume of 0.896 cc, which is 52% of the average Icterine Warbler egg volume (1.738 cc). The mother of the clutch was ringed a year before as a nestling in a nest of four, 300 m from her 2015- nest. The 2nd calendar year bird had a normal body condition when it was caught on the 7th of July 2015 (13.1 g, wing length 77.5 mm). The runt egg did not hatch, but the other three eggs did. The three chicks developed well and fledged successfully. In the four following research years neither the ringed offspring nor the female were recorded again within the study area.

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