Failure...

Two-egg clutch of Barn Owls (Tyto alba guttata) in a wall mounted nest box located in a green suburb of Zwolle, The Netherlands. An infrared camera connection showed that one of the two breeding birds disappeared during early egg-stage (halfway April), but the true cause of failure remains unknown. The box was installed over 20 years ago and became occupied by a single Barn Owl pretty much every winter and occasionally in summer. During summer 2015 a second bird appeared and a first breeding attempt was made the following year, which also failed during early egg stage. Today the box got cleaned out, the eggs were removed and 85 pellets were collected and will be used to identify prey items.

Latest peregrine nest box in Zwolle (The Netherlands) gets occupied!

Recently I devoted a blog entry to the developments of the Peregrine Falcon Falco peregrinus population of Zwolle, The Netherlands. On February 18, 2014, I helped Jan van Dijk (Raptor Workinggroup Zwolle) with installing a new nest box on a transmission tower in the north of the city, where a potential breeding pair has been observed for about a year now (http://www.timvannus.blogspot.nl/2014/02/the-peregrine-eyries-of-zwolle.html).Today Jan informed us the birds already accepted the box (and not the top of the tower's staircase) and that there is a lot more going on with the Peregrines in Zwolle: http://ringert34.blogspot.pt/2014/03/toppie.html

Incubating adult female Peregrine falcon in the new nest box in the north of Zwolle (photo: Jan van Dijk).

Ring-necked Parakeets and some raptor action in Amsterdam North, The Netherlands (January 15, 2014)

Preceding the upcoming national count of roosting Ring-necked Parakeets Psittacula krameri, yesterday’s afternoon Ruud Vlek and I visited the known parakeet roost in Amsterdam North. After crossing ‘The IJ’ by ferry and before meeting up with Ruud, I inspected ‘Overhoeks’ (former Shell headquarter) for the presence of Peregrine Falcons Falco peregrinus. At about 15:30 a single Peregrine appeared, circling above the tower. A few minutes later it perched on the tower’s concrete overhang. The bird was obviously in a hunting modus and flew off towards the west, away from my location. At 15:45, on a second walk around the tower, prey feathers were flying off the roof, indicating a prey had been caught.

Carrion Crow Corvus corone, below the tower.

After meeting up with Ruud at dusk and our arrival at the roost, there were few parakeets present. But large numbers came in only shortly after, forming pre-roost gatherings in surrounding trees. At that time we counted 722 Ring-necked Parakeets.

Based on our past experiences at the roost site, we know that the gathering of the parakeets not only attracts our interest, but also that of several raptor species. At 16:52, just when the first few hundred birds had settled in the roost trees (where we were hoping to eventually conduct a total count) a Goshawk Accipiter gentilis appeared, diving straight into this group of birds. What followed was an explosion of parakeets, which all evacuated the roost site. We found back some of these birds in scattered groups in other trees in the area. These groups were then only photographed, but while doing this a number of birds returned from their hideouts and joined the groups that had already been inspected by us. At that point it became too dark for a recount.

Today I analyzed this last round of photos and these show the presence of at least 532 parakeets. Marking every visible parakeet in Paint and counting the dots is one of the preferred methods, but it can only be done when the photos allow it. Due to distance and parakeet density, on the second photo it got too difficult to distinguish all individual birds, so I probably missed a few there. Our first count (722 Ring-necked Parakeets) will be the result of yesterday’s action. I hope things will go easier on Sunday, the day of the national count.

Beachcombing @ Rottumeroog, The Netherlands

Photos from the island Rottumeroog