Winterkoning Troglodytes troglodytes helpt Koolmezen Parus major bij het grootbrengen van jongen

A Wren helped feeding the offspring of a pair of Great Tits, nesting in a nestbox. The nestbox was attached to the wall of our house. To reach it the Wren had to cross a 4 m open space between the nestbox and an overgrown fence. First feedings by the wren were observed seven days after hatching. In the beginning the wren hesitated before entering the entrance hole, but after some days the feeding procedure was carried out fluently. The wren wasn’t observed to carry out faeces. From the second day onwards the Wren fed more frequently than did the tits (up to eight times more often). Flowever helping at nests of relatives is not normal for European Wrens, helping in feeding offspring of other bird species is observed relatively often (Glutz von Blotzheim & Bauer 1985). Reasons for this behaviour are unclear.