OSLO BIRDER: Breeding Hobbies Maridalen 2023

So, it is time for me to blog about the scarce and late breeding birds I mentioned a few times during the summer. No prizes for guessing that I was referring to Honey Buzzard and Hobby. I had a post about breeding Hobbies last year and one about Honey Buzzards in 2021 but this year both bred and I was able to follow them from a much earlier stage.

I was fully prepared for the Hobbies to breed at the same site as last year and after the first sighting of Hobby I Maridalen on 9 May I was waiting for signs that they were settling down but things seem to go slowly with this species. It wasn’t until 30 May that I saw a pair together and not before 5 June that they were in the area around last years nest. Last year’s nest (an old crows nest had suffered during the winter and did not look to be suitable any more but there was a much sturdier nest only about 15m away and I assumed that this would be used. During the next couple of weeks there were nearly always calling birds present in the wood, sometimes very close to the sturdy nest but often 50m away. On one occasion I even had three Hobbies flying over the wood but no matter how much I searched I could not find where they were breeding – even though I had felt sure they would use the sturdy nest I could never see a bird sitting in it.

I was then away for a month but on 22 July I saw both adults in the breeding wood making a lot of noise and found one of the adults was plucking a bird which it then flew off with towards the crows nests and this was surely a sign of hatched young but I still could not find where the nest was!

The next day though when I looked at the sturdy nest I finally saw a bird sitting there and there was clearly something (young) under it. Seeing the adult now I realised that an incubating bird would have been invisible to me due to the size and depth of the nest so this explains why I could never see it when I looked in June.

On 24^th I witnessed an adult that was clearly feeding (unseen) young in the nest but it would be a couple days before I actually saw them. On 26^th I saw a downy wing stretching above the rim of the nest and then both adults were very noisily dive bombing an unseen predator (assumed to be Goshawk) about 300m from nest.

On 1 August two young were just visible (the same number as last year but one less that in 2021) and after this I visited regularly and saw the parents coming with food on a few occasions. The female would always be perched atop a tree close to the nest and the male would announce his arrival by calling with the female then flying to him and receiving the food in an areal pass (it was rare that I got to actually witness this though due to the trees obstructing my view). She would then take the food to a perch and pluck the feathers before flying to the nest.

I witnessed the adults getting very worked up about Goshawks and also a Honey Buzzard that flew low over the nest but regularly overflying Ospreys seemed to not be a concern.

On 11 August the first young had left the nest and was perched on a branch a couple of metres from the nest and on 13^th both young were out of nest perching in nest tree. By 19^th both young had moved quite a way from the nest and I found them perched in the same tree calling and one of the young was seen flying strongly. On 22 Aug both young were seen flying and food being delivered. It seems the female is still guarding the young whilst the male provides.

After this the frequency of sightings declined drastically and even though I widened my search radius I could not find the family again. I had an adult perched on a tree top on 29^th, a juvenile flying around calling on 30 Aug and then my final sighting of a juvenile seen in flight on 5 September. So it was a bit unsatisfactory that I did not get to see the young perfecting their flying and hunting techniques as I had in the previous years but another successful breeding season bodes well for future years.

Comparing the photos of the young this year versus last it looks like the young hatched 4-5 days later.

First of all a video which has scenes from 23 July, 2,3,9,11 & 23 August. The video is 4:22 long but includes an unedited scene of a parent feeding the young on 2 August which is 2 and a half minutes long.

6 June

This bird (the male?) was perched with something right next to what later turned out to be the nest. I have no idea what it was and do not think it is food but it may be the lining of the old Crows nest that it had removed

23 July pictures

the female on the nest and there were clearly young underneath her

female

male

female

telling the male and female apart is never easy and often impossible but this comparison hopefully makes them clearer. The female is on the right and has a white eyebrow and paler forehead than the male

24 July pictures

this is why I never noticed that the nest was occupied during the incubation stage. A tail of an adult is only just visible despite there being two young under her