A rarity!

This autumn has seen a very significant irruption of various tits into Norway. The timing and size of the irruptions is easiest to see by looking at numbers at coastal areas with good coverage with Lista Bird Observatory being a perfect place. Coal Tits were the first obvious arrival already at the end of August and peaking in the first week of September and which I witnessed when I was there. Blue and Willow Tits followed with a peak at the end of September and even Great Tits were clearly on the move. Long-tailed Tits came later with a peak in the middle of October.

Even around Oslo it has been easy to detect the irrupting birds with Coal, Blue and Long-tailed Tits especially obvious. I also reckon that the Marsh Tits that have turned up in Maridalen may well be associated with the irruption of the other species even if none have been registered at Lista.

It is easy to assume that all these birds have come from the north east but records of Long-tailed Tits with stripy heads of the continental race europaeus show that birds have also come from the south or south east. The white-headed race caudatus that we get in Norway is also the race that occurs east and then south east into Russia with the two races meeting and intergrading, in Poland.

Prior to 2025 there are only two accepted records of the race europaeus in Norway although there have been birds showing some characters of this race (the head stripe is not well marked enough especially around the eye) including this bird I had in Maridalen in 2016 (and which probably bred) but which are perhaps best to treat as intergrades between the two races. So far in 2025 there have been another 6-7 records with the first two on 12th October. There is some debate as to whether these birds have dark and wide enough head stripes (as well as other plumage features) to be classified as "pure" europaeus or whether they are best considered as intergrades. I do not feel qualified to pronounce on this and it is no easy decision to make but that is something that NSKF, the rarities committee will have to pronounce on. Pure or intergrades though they do show that these birds originate on the other side of the Baltic. I have checked Swedish records this autumn and rather surprisingly there have been few records in Sweden of pure birds however there have been a record number of birds reported as intergraes (an option not available in Norway).

Ever since I saw the first records on 12 October I have been trying to check every flock of LtTs I come across for birds with stripy heads. It is not an easy task as there have been lots of LtTs this autumn and also they are so quick moving that it is difficult to grill every bird. I have not seen a hint of a stripe until yesterday when amongst a flock of about 8 birds in Maridalen I saw one with stripes. Getting photos of it was more challenging and I actually think there may have been more than one bird but I did get a couple of photos of one bird which has well marked head stripes although I am sure I saw an even better marked bird. I hoped to find the flock again today but had no joy and believe these immigrant flocks are still moving around.

A Long-tailed Tit (stjertmeis) that has come from a long way to the east or south east

I am not sure if this out of focus shot is of the same bird or perhaps of another in the same flock

a Redwing (rødvingetrost) was a surprise at the end of November in a year with no berries. The white marks on the tips of the tertials show it to be a 1cy bird (born this year)

it did find a (frozen) worm but will not survive long unless it heads south

Settling down

Birdlife in Maridalen has really settled down with all signs of migration having come to an end. The very popular Pygmy Owl (one of at least four being seen in the valley) by the bridge and feeders continues to show most days as do the Marsh Tits. I have now ascertained beyond doubt that there are three Marsh Tits which is a Maridalen record and 🤞maybe the start of a permanent range expansion. The quiet bird is still hanging out by the horses usually in the close company of at least one Willow Tit and is now feeding in trees rather than amongst (now frozen) horse muck. Only 300 metres away there are now two noisy birds regularly coming to the feeding station where they can be seen alongside the other five tit species.

Only around 25 species is now the expected haul from a session in the Dale which really is not very exciting. A visit to the fjord at Huk gives roughly the same number of species but of a very different composition and on Thursday I had both Oystercatcher and Purple Sandpiper. There are many hundreds of Herring Gulls in the fjord feeding on a super abundance of starfish that are exposed by very low tides. This super abundance is apparently a further postive affect of a huge breeding (wrong word I know) of mussels last year which in addition to being food for seaducks are also food for the starfish.

Pygmy Owl before sunrise

In this video the owl chases off a Magpie (skjære) that landed close to it

Marsh Tit (løvmeis) with Great Tit (kjøttmeis)

Nuthatch (spettmeis)

birds need to drink and when there is ice but not yet snow to eat then theyneed to exploit any open water they can find such as this Blue Tit (blåmeis)

the view from Huk, Bygdøy on Thursday morning

Purple Sandpiper (fjæreplytt) and Oystercatcher (tjeld):

Herring Gull (gråmåke) eating a starfish:

and some reflections in Maridalen

Pygmy Owl with mouse and vole and still in the sun…

Yesterday was a particularly rewarding day. A start at Fornebu on a cold, wind free and cloudless day revealed all the bays were frozen and there was hardly a bird to see although I did hear Bearded Tits so we can only hope that they stay and start feeding high up on the seed heads rather than on the ground.

Maridalen was where the action was though. There are very few birds here too and although the lake remains ice free I only counted exactly 10 birds on it! A Guillemot (presumably a long stayer) and a Great Crested Grebe topped the bill. Passerines other that tits were hardly more numerous although I did not find the Marsh Tit – I assume the fact that the horse manure it has been finding food in is now frozen has caused it to exploit a new food source.

But it was a Pygmy Owl that stole the show and it performed to a group of generally well behaved photographers and the odd birder for pretty much all of the short day. And there are clearly rodents. I witnessed it take 2 Field Voles and a Wood Mouse with 40 minutes between each catch. One of the voles was eaten but the two other catches were stashed in a nest box for leaner times. It often was hunting right by the road where its two legged admirers were stood and after catching one of the voles it then flew with it at head height through our throng (a slight exaggeration we were never more than 10) to a small wood on the other side of the road where it ate in privacy before soon appearing high in a tree where it looked suddenly very plump and content and preened and enjoyed the sun.

 

Today though was if anything even better. Jack needed to add his 198^th species to his Oslo list so we met up to try to find the Marsh Tit for him. And we suceeded in finding two! The usual quiet bird by the horses and only 300m away a very loud bird. We saw and heard this bird long enough to be confident that it was single so my theory of a single bird and a pair does not look to hold water but two separate single birds is interesting. Why do they not hang out together?

We also had great views of the Pygmy Owl in lovely golden light and had it catch a Field Vole right in front of us and generally go about its business seemingly completely unaffected by out close presence.

I’ll start with documentation of today’s events: 

Pygmy Owl (spurveugle) with freshly caught Field Vole (markmus)

the new and noisy Marsh Tit (løvmeis) which can be heard in the video

and the other mostly silent bird which doesn't seem to move far at all

Yesterday in chronological order:

first seen perched quite high

it then flew  into this nest box but without taking anything in. Through a crack in the side of the box it could be seen moving around and was in there for a few minutes.

after it came out it was searching for food in the area of the nest box and right by the road and a number of admirers

here it has taken a Wood Mouse (småskogmus) from the ground and flown up into the tree

much longer tail and larger ears on a mouse than a vole

the mouse has been repositioned and the owl is ready to fly..

..over 50m back to the nest box

here it can be seen inside. I believe it deposited the mouse in one of its larders rather than eating it

but there is no obvious layer of dead rodents or birds covering the base of the box although there could of course be some to the left

peering out

plunging down to a branch under the box

and immediately in hunt mode again

here it had clearly heard something and was leaning further and further forward

and (s)hes off

it disappeared into the dead grass but this shot just about shows the vole in its talons

here it has taken control of, and killed, the vole and is getting ready to take off

a plump and content owl enjoying the sun after having eaten this vole rather than storing it