Verschillen in gedrag van jonge Boomvalken Falco subbuteo na het uitvliegen

In farmland near Wageningen, central Netherlands, breeding Hobbies Falco subbuteo were observed between 2008 and 2012. Most pairs nested in trees (poplars, planted in rows alongside roads), but some were found on crow’s nests in electricity pylons. Post-­fledging behaviour was studied in a pylon-­nesting pair in 2011 (2 chicks fledged from a 50 kV pylon, on 19 August 2011) and in a tree-­nesting pair in 2012 (2 chicks fledged, between 7 and 9 August 2012). In the pylon-­nesting Hobbies, the male was seen to bring vertebrate prey to the chicks after fledging, the female was mainly involved in catching dragonflies. For example, on day 4 after fledging, the female made 15 hunting flights during 95 minutes of observation, feeding chicks at least 8 times with insects. On day 13, chicks were begging vociferously between 16.00 and 17.00 hrs, but fed only once (a dragonfly). On day 22 (10 September), 59 dragonflies Odonata and crane flies Tipulidae were captured during 3.5 hrs of observation. On 12 September, the family was still intact, and capturing Tipulidae, but from 13-­30 September, only juveniles were recorded on the breeding site (but not later), suggesting that adults departed the breeding site before juveniles. Young were fed up till departure of the adults (a month after fledging). The young from the tree-­nest ranged farther (and started earlier to range widely) than chicks raised on the electricity pylon (about twice as far). No feeding of pylon-­raised young was recorded anymore from three weeks after fledging onwards. From then on, the site where begging occurred was not indicative of the breeding site, which could be hundreds of meters away.