Succesfull breeding

Some pleasant surprises in Oslo and Maridalen regarding breeding birds means I am not completely over into the butterfly world just yet.

On the lake there was suddenly a single adult Mute Swan with 5 small young! This is just like last year in that they suddenly appeared but this year I was better prepared and had discovered the nest on 26 May. After that discovery of the nest though I had been unable on subsequent attempts to see any birds on it (although it was very difficult to see) and had only a record of single adult on 1 June and then a pair flying over the lake (not near the nest) on 9 June. I therefore assumed that the nesting attempt had failed and the birds had moved off. To suddenly see an adult with young was therefore a shock and it was equally surprising that I could not find the other adult anywhere on the lake. Has the male died or moved off? And if so how did the female managed to incubate and feed without me ever seeing her? And the pair I saw on x June – were they visitors? Perhaps the other pair that started nesting and then gave up? An answer to the first question is that P578 who I saw on Maridalsvannet on 29 April, and his ring was again read on 24 May, who is the male of the pair that bred last year and I assume the father of this years young was seen on 16 June at Fornebu where he and his mate had spent the winter – so it looks like he has left his mate to fend for herself! Did this happen before the eggs hatched?

Mute Swan (knoppsvane) - presumably female PC79 who bred here last year - with 5 small young but not with her mate (P578) who has flown down to Fornebu!

The Black-throated Diver pair (one of perhaps two on the lake) still have a single youngster and have moved quite a way from the nest with it.

Black-throated Diver (storlom) family

The ever growing cereal crop on the Lapwing field makes seeing the birds very difficult but yesterday I could see 3 (2 + 1) almost fully grown young which is a great relief but the fate of the two last nests remains unknown.

a nearly fully grown Lapwing (vipe) young

And finally, I had Red-backed Shrike in the Dale this year and it seems to be a nesting pair so fingers crossed for their success.

pair of Red-backed Shrikes (tornskate) in Maridalen

and the male on his own

A visit to Østensjøvannet today also revealed lots of young birds. Best of all were the Black-headed Gulls which have had their first successful breeding season (at least as a colony) for a few years with many large young on two islands. Great Crested Grebes, Coot and Mute Swans also had young (the later no larger than the ones I saw on Maridalsvannet) and surprisingly a female Goldeneye had 11 quite large young with her. This raises two questions – are they all hers? Perhaps unlikely. And how have so many survived so long? Normally the vast majority get eaten either by gulls or pike.

Black-headed Gulls (hettemåke) have had a successful breeding season at Østensjøvannet

and a male Gadwall (snadderand) which once again seems to have chosen Østensjøvannet to moult although this year there were no records earlier in the spring

A swell day without Svellet

Today I decided to leave Svellet alone and instead visit the Oslo islands. I cannot see that anyone else has visited Svellet today so don’t know if my decision was the right one but I can see that water levels have only risen by  2cm so conditions will still be very, very mighty.

The islands gave a perfectly acceptable account of themselves even if the fjord contained not a single duck, diver, grebe or tern of any interest what so ever. Before I had even got to Gressholmen I saw a massive 4 species of waders (but only one of each)  in the tiny muddy bay by the ferry stop at Lindøya Øst (Redshank, Greenshank, Ringed Plover and Oystercatcher) and this did increase expectations rather considerably. Gressholmen’s muddy bay disappoints (me) more often that otherwise but mid to late May is probably when it is at its best. There had been no rain or southerly winds (they are from the north at the moment) so I did not expect too much but a Bar-tailed Godwit that has been present a few days was still there alongside the same species, but in greater numbers, as I had seen at Lindøya.

A singing Thrush Nightingale in exactly the same scrub as the last two years was my first of the year and a joy to listen to.

A worrying aspect of the trip was quite how few Black-headed Gulls there were. I only found two colonies and the largest was considerably smaller than it has been in previous years. I have also seen that Oslo’s normally largest colony on an islet off Bygdøy is empty this year so unless there is a large colony somewhere else then it looks like a crisis for the species (the inland colonies at Sognsvann and Østensjøvannet are small in relation to the number that normally breed on the fjord).

The absolute highlight and a slight headache came when I was getting on the ferry at Lindøya. I heard angry Hooded Crows and Swallows behind me and turned expecting to see a Goshawk. What I did see was something smaller but after a second I realised it was an owl and must be one of the earded ones. I raised my bins whilst walking and saw the face and was sure it was a Short-eared. I then got on board and reached for the superzoom and filmed whilst the ferry left the dock but only managed 20 seconds before the deckhand said I had to move inside. I was quite happy that I had managed to document only my second ever Oslo Short-eared and decided to look at the video to see if it was any good and of course to see if I had actually pressed record… Well this time I had but the owl proved to be of the longer eared variety. Still a very good bird in an Oslo context. My still only ever record of Short-eared Owl was an equally difficult experience although then I assumed it had to be a Leo and it was only the pictures that allowed me to see it was a Seo… 

a clip from the video showing the grey face and under wing tips that have fine baring and not a particularly black tip all of which say Leo (hornugle)

and here it disappears to the north over Hovedøya and towards the city

The sound of the Thrush Nightingale (nattergal) and a Willow Warbler (løvsanger)

the Bar-tailed Godwit (lappspove) on Gressholmen

The Black-headed Gull (hettemåke) colony on Nakkeskjær where I counted 65 nests although there were undoubtedly more out of sight on the far side

a close up of some of the nests

and here 9 nests on the main part of the island where they do not look to be so safe

a female Wheateat (steinskvett)

In Maridalen it was again difficult to be certain what was happening with the Lapwings but I did see more today. There were 10 adults and five young in broods of 4 and 1. There was also another female acting as though she had young in the long grass and probably two females that were on new nests but that will have to firmed up as a bit more time passes.

the single young Lapwing (vipe) with mum and a "singing" Snipe (enkeltbekkasin)

a new nest

two males have been frequently been squaring off

Loads of birds!

I frequently am accused of being overly optimistic in my bird forecasts and expectations but I see that my predictions in my last post for Svellet were actually very pessimistic. The wader fest is far from over as the water levels have stopped climbing (at least for now) and there clearly is enough food available as wader numbers which fell on Wednesday rose sharply yesterday (when I did not visit) and were still high today. Viewing conditions are far from great which is par for the course there but today I was able to pick out a Temminck’s Stint although another one on nearby Merkja was much easier to view (as were two yesterday evening which I twitched at Fornebu).

Yesterday gave me a non-wader mass bird event and a quite unique one at that. Very large numbers of Willow Warblers have been seen crossing the fjord from Nesodden and they have been then concentrating at Østensjøvannet. It would appear that frost nights to the north (temperatures were under zero on Tuesday evening as we drove home form owling) are stopping the nocturnal migration of the Willow Warblers and they seem to be stopping their northward journey in the Oslo area and then continuing northwards during the day and moving whilst also searching for food. There is not an overabundance of insects yet in Oslo but Østensjøvannet clearly has good numbers. There were over 1000 Willow Warblers as I walked around the lake and every tree and bush was dripping with them. They were also feeding in long grass, on the short grass of playing fields, on a newly ploughed field, on the paths and many were sallying after insects in the manner of a flycatcher from any available perch including fence wires. It truly was an amazing experience both visually and orally as birds were also singing everywhere. There were not many other species that had clearly arrived with the WWs except for Blackcaps which were more common that normal but not in exceptional numbers. That there were lots of insects to eat though was shown by House Sparrows that were flycatching and Bramblings taking insects alongside the WWs in bushes.

This video gives some idea of how it was but does not pay the experience the justice it deserves:

Svellet 8th May as viewed from the eastern shore

and viewed from the west - still lots of mud and shallow water which clearly has more food than I expected after the water levels rose so quickly

A really heart warming sight at Østensjøvannet are the Black-headed Gulls (hettemåke) that are nesting again. There are three small colonies (including this one) and scattered single nests around the lake and the total number of nests may not be much more than 50 but this is in stark contrast to last years dire situation but also the 2000 odd pairs that used to breed here. Fingers crossed that there are lots of fledged young in a month or two. There is also a good colony at Sognsvann - it would appear that the two most visited lakes for recreational use are attractive to both humans and gulls - but I have yet to notice any nesting on the fjord so I fear that overall things are not good for the species

yesterday and today I could not see a single young Lapwing (vipe) in Maridalen but there is a new nest although as this field was only ploughed on Sunday I am not sure whether she is incubating or just in the egg laying phase

and the Mute Swans (knoppsvane) are now finished with nest building and are on the nest although I do not know whether any eggs have been layed yet

The last week

The last week hasn’t just been about big owls and rare waders. I have continued visiting Svellet and Nordre Øyeren but despite continued low water levels there have been surprisingly few waders with now zero Wood Sandpipers!!! Water levels are now rising about 10cm a day so the mud at the edges probably just has no food in it. Also with spring having come early and no rain to force birds down many birds are probably also flying directly to their breeding sites. The first Temminck’s Stint and Dunlins have turned up though and Redshank have become the commonest wader.

Yesterday, I had my first visit of the year to the islands and a 2nd summer Little Gull on Gressholmen was a real highlight and gave much better views than the birds in Svellet last week.

when I first saw this gull with an extensive black hood, red legs, a pink wash on the breast and black in the wing tips I thought I had found an adult Bonaparte's Gull. A check in the scope though showed it was "just" a 2nd summer Little Gull.

and comparison the views that I managed at Svellet last week where I must admit to being quite chuffed that I actually got a photo which shows both an adult and a 1st summer. This video gives an idea of the viewing conditions at Svellet:

A Redshank (rødstilk) at Gressholmen was the only migrant wader and for me this has been an awful spring for waders in Oslo with me still not having seen Greenshank or Whimbrel. Water levels are finally falling at Maridalsvannet revealing some muddy edges but I fear it is too little too late

Thrush Nightingale (nattergal) on Gressholmen in exactly the same place as they bred last year so presumably the same male

there were quite a few young birds to be seen on the islands including the first Black-headed Gulls (hettemåke) with three young visible top left

this must be one of the larger BhG colonies left in the Oslo area

at Østensjøvannet which used to hold many hundreds if not thousands of pairs of nesting Black-headed Gulls I could only find 7 occupied nests today with five in this tree. The especially maintained islands that they used to use are now empty

this colour ringed BhG at Østensjøvannet received its bling at Bowness-on-Windermere in the UK in December 2019 and has subsequently been resighted there every winter and in Oslo in the summers

Eiders (ærfugl) have had young very early this year. Normally the adult males would have moved off but here they were displaying to the females

A Dunlin (myrsnipe) and Redshank (rødstilk) at Årnestangen in the same place where I found the dowitcher

and my first Temminck's Stint of the year also at Årnestangen

it is not easy being a breeding Ringed Plover (sandlo) in the Oslo area. This bird at Fornebu had chosen a fenced off area away from human disturbance and has hopefully been succesful. This picture was taken just a few days before the young should have hatched and a visit a week later revealed no birds at all which hopefully means they have led the young somewhere even safter

when on the islands a Ringed Plover flew up in front of me and I saw that it had flown up from a nest which contained 3 eggs

hopefully they will be successfull

in Maridalen there is now a third Lapwing nest. This is one of the pairs that lost their nest to the plough relaying. I still think that the other pair that seemed to lose their nest may actually have young in the long grass although I have yet to see them. A fourth pair is now hanging out at Kirkeby and will hopefully nest there

the Long-tailed Tit (stjertmeis) nest that I found had an adult in it on 8 May and I assumed it was incubating. However subsequent sightings mean she was most likely brooding..

as on 13 May the young were being fed by both parents at the opening to the nest. This must be very early

water levels at Svellet are rising by 10cm every day and the party is ending

this is how it looked on Tuesday 13 May when I last visited and as can be seen on the graph water levels have risen more than 20cm since then which probably means most of the mud is now under water

and the view to the south