Dutch Birding volume 28 (2006) no 4

Mixed breeding of Short-toed Treecreeper and Eurasian Treecreeper at Olst in 2005

On 11 April 2005, a singing Eurasian Treecreeper Certhia familiaris was discovered at Olst, Overijssel, the Netherlands. It appeared to be paired with a Short-toed Treecreeper C brachydactyla and they were building a nest. On 25 May, one young was seen leaving the nest; apparently, it was the only young raised. The juvenile hybrid was again seen on 9 July.

Initially, the Eurasian Treecreeper was considered to belong to nominate C f familiaris because of the whitish appearance. However, because of the dirty-white left flank and vent, doubts remained about this subspecific identity. Furthermore, regular breeding sites of the central European subspecies C f macrodactyla are not very far away and this taxon slowly seems to spread westwards. Also in 2005, a singing male macrodactyla was observed at Lonnekerberg, Overijssel, and in 2006 a pair successfully bred at that same location, which is only 55 km east of Olst.

This is the first documented successful breeding record of a mixed pair Short-toed x Eurasian Treecreeper.

Edwin Winkel, Het Laar 217, 7414 BP Deventer, Nederland
(hravnhome.nl)
Wouter Teunissen, Koningstraat 13, 2316 CC Leiden, Nederland
(teunissen.woutergmail.com)
Mark Zekhuis, Stoevelaar 23, 7414 CA Deventer, Nederland
(catbirdhome.nl)