Monday, August 24, 2015

Lugn lilla skarven

During last days we have been out some nights to catch some birds in extra ringing. We used both nets for waders and a big lamp for lamping, and the results have been quite interesting so far. This post will be focused only in the two Great Cormorants (Phalacrocorax carbo) we trapped by lamping.

It is well known the fact that juvenile and subadult Great Cormorants have white feathers in belly, so both birds can be quickly recognised as immature birds. There's a lot of variation in the white pattern on the belly, that can also be affected by the moult. They have a partial postjuvenile moult that involves head, mantle and some breast and belly feathers. The big variation was very noticeable in our birds:

First bird, first-year (EURING 3).
Second bird, first-year (EURING 3).
Our birds were both first-years (EURING 3). The first bird (darker) was not an EURING 5 because there was no sign of the first complete moult (all wing juvenile), and wing feathers were very fresh. Given that variation in the belly, ageing first-year / second-year individuals in the field at this time of the year, especially on resting birds, can be quite tricky. Signs of the complete moult or worn flight feathers would be the best criteria.
First bird. First-year (EURING 3).
Second bird. First-year (EURING 3).

Subspecies identification
Two subspecies have been traditionally recognised in Europe: P.c.carbo and P.c.sinensis. The separation of both subspecies is not straightforward, and many literature about the subject appeared the last decade. Among all the research that was done, Marion & Le Gentil (2006) studied haplotypes and they found 3 different groups, corresponding to the two mentioned subspecies and the a putative new taxa, that they named 'Phalacrocorax carbo norvegicus'. As far as I'm concerned, the subspecies status is not fully accepted yet. Quoting the autors: 'norvegicus' would be "mainly present in the Nordic range (Norway, but also on the coasts from Sweden to Brittany)".

Danish and swedish breeding colonies were known to be from the Continental subspecies (sinensis), and the presence of a North Atlantic (carbo) is very unlikely in Falsterbo. Nonetheless, as it has been suggested, 'norvegicus' could be present, and indeed, the closest breeding colonies to Falsterbo peninsula are localited in coastal areas, where (according to Marion & Le Gentil 2006) 'norvegicus' is more prone to breed rather than sinensis, which usually breeds in trees.

I haven't been able to find any biometric data on the literature for 'norvegicus', but following again the same Marion & Le Gentil, 'norvegicus' should be similar to carbo in many aspects. Actually, Norwegian populations were meant to be from the North Atlantic subspecies. Bill measurements were taken (bill length from the tip to the first feathers, and bill depth in the narrowest part in the middle), but as the bill sizes depends also on the sex, there's too much overlap for this measurements to be significant. Gular pouch was measured in both birds with the pictures taken, assuming possible deviations due tue the position of the bird. Nonetheless, results follow the notes that were taken in the field.

The first bird have a rather acute angle, around 60º, what suggests a possible 'norvegicus' to me. Also, the bill was strong, and the bird was quite big and bulky.

The second bird has a gular pouch angle around 70º, which is good for a sinensis. Also, the bird was smaller and the bill was slimmer than the first bird.

More research should be done to confirm 'norvegicus' as a new Great Cormorant subspecies, and to take more biometric data to allow their identification without genetic analysis.

To Timmy Micallef for allow me to post his pictures and for his decisive help during lamping nights, as Emil Lundahl and Erik Sjögren did too, and to Caroline Sjöström and Michael Tholin for the visit during the second night, providing the name of this post.

Cramp, S. (ed). (1977). Handbook of the Birds of Europe, the Middle East and North Africa. The Birds of the Western Palearctic. Volume 1: from Ostriches to Ducks. Oxford University Press.
Garner, M (2015). Japanese Cormorant genes in Europe?. Birding Frontiers, online.
Marion, L. & Le Gentil, J. (2006). Ecological segregation and population srtucturing of the Cormorant Phalacrocorax carbo in Europe, in relation to the recent introgression of continental and marine subspecies. Evolutionary Ecology 20: 193-216.
Millington, R. (2005). Identification of North Atlantic and Continental Cormorants. Birding World 18 (3): 112-123.
Newson, S., Hugues, B., Russel, I, Ekins, G. & Sellers, R. (2004). Sub-specific differentiation and distribution of Great Cormorants Phalacrocorax carbo in Europe. Ardea 92 (1): 3-10.
Newson S., Ekins, G., Hugues, B., Russel, I. & Sellers, R. (2005). Separation of North Atlantic and Continental Cormorants. Birding World 18 (3): 107-111.

Saturday, August 15, 2015

Getting away from the average

The Falsterbo Bird Observatory webpage contains a huge lot of information. I can spend hours looking at differents things, and the information never ends...

One very interesting section is the Ringing totals for every day. Just open the main page and click "Ringing". There you will see two different tables, one for each ringing campaign, both Lighthouse Garden and Flommen reedbeds. Three columns are on the right of the species: daily summary, season summary and season average up to date. Comparing the season summary with the season average give you a very close idea to what is going on.

This season we started very close to the average, sometimes over. The big numbers of Sand Martins (Riparia riparia), Barn Swallows (Hirundo rustica) and White Wagtails (Motacilla alba) we had in the beggining of the season made this possible.

Nonetheless, we are already more than 300 birds below the average, with more than 400 Reed Warblers (Acrocephalus scirpaceus) below. It seems it has been a very bad breeding season for this species, probably because of the cold months in May and June (as some Swedish birders told me). The most worrying fact is that we catch just a few first-years, and this make the number very low.
Actually, many local Reed Warblers are still incubating during the start of August..., the same with some local Marsh Warblers (Acrocephalus palustris).
If we look at the long-term trends generated in the Falsterbo Bird Observatory webpage, a slightly decline has been occurying during last few years...

7+ (EURING E; 6 year-old or older) Reed Warbler,
ringed at Flommen in 2010 as adult.
Falsterbo B.O. 2015. Ringing totals at Falsterbo, SW Sweden.

But not everything is that bad! The rest of species are over or very close to the average, like Sedge Warbler (Acrocephalus schoenobaenus) for instance. The numbers of Marsh Warblers, although having late breeders around, are also on the average. The other 'worrying species', which is even more noticeable in the Lighthouse Garden numbers, is Willow Warbler (Phylloscopus trochilus)...

Adult (EURING 4) Sedge Warbler on the top, first-year
(EURING 3) on the bottom.
First-year (EURING 3) Willow Warbler.
It will be very interesting to see the numbers at the end of the season!
In the meantime, we will keep enjoying the nice birds we are having lately. For first time for me, in my third season here, we have ringed 2 Great Reed Warblers (Acrocephalus arundinaceus)! Not a very exciting species for me, but I have enjoyed them.

Other usual Flommen stuff we have caught, but nice, are a juvenile Green Sandpiper (Tringa ochropus), one of those 'hedgehog' Water Rails (Rallus aquaticus) and a Common Rosefinch (Carpodacus erythrinus).

First-year (EURING 3) Green Sandpiper
Adult Water Rails have a complete simultaneous moult,
and remain flightless for 1,5 - 2 weeks. We also trapped
one last year.
First-year Rosefinch, a nice species that is not caught every
year in the reeds!!
Migration is starting seriously now. Tree Pipits (Anthus pratensis), Yellow Wagtails (Motacilla flava) and Whinchats (Saxicola rubetra) are already on the move in nice numbers. Red-backed Shrikes (Lanius collurio) appear in some isolated bushes... and you feel everything can happen at any moment. The fun is just starting!

First-year (EURING 3) Tree Pipit 
First-year (EURING 3) female Whinchat
First-yeart Red-backed Shrike 
  Some Flommen views to end...

Sunday, July 26, 2015

Orange is the new black

In late July, many adult waders are already in migration, specially the orange coloured ones: Red Knot (Calidris canutus), Curlew Sandpiper (Calidris ferruginea) and Bar-tailed Godwit (Limosa lapponica). Also, good numbers of Dunlins (Calidris alpina) are around.
Nabben and the Mäklappen beach, to the south-west corner of the peninsula, are two of the best places for birding in the area. There were lots of waders a few days ago, with an specially nice flock of about 150 Knots. I tried to make a video using my phone and the scope, here you can see the result.
We went out at night to catch them, together with Timmy, Emil and Erik. And we actually managed to catch some!!

We got 19 adult Dunlins (Calidris alpina). As far as I know, second year birds are possible to determine because of the worn flight feathers, small and droplet-shaped white on the tip of the primary coverts, and for the presence of inner juvenile-type median coverts, with tawny edges. For further and much more detailed information about Dunlins, I fully reccomend the website
Adult, 3+, (EURING 6).
Second year (EURING 5).
3+ on the left, second year on the right. Note the differences in wear and
colour edges of the upper tail coverts.
7 Red Knots (Calidris canutus) were trapped as well, a very nice species in hand. As some first winter birds can do a complete moult, and if there's no retained feathers, adults should be aged as 2+ (EURING 4).
With Curlew Sandpipers (Calidris ferruginea), and in ageing terms, it happens something similar with Knots. Seemingly, some 1w can undergo a complete moult in Africa. Thus, the bird we trapped this year (on the top), with 3+ (EURING 6) appearence, should be aged as a 2+ (EURING 4), at least until more research is done. Nonetheless, the bird I trapped last year (on the bottom) can now be safely aged as a second-year (EURING 5).

Also, this ferruginea can be sexed as a female. Males are richer coloured in underparts.

Is was a great surprise when we found this Bar-tailed Godwit (Limosa lapponica) in the nets. It was actually smaller than expected, but nicer!
It was a 3+ (EURING 6), second-years have very worn primaries, and usually they don't attain full summer plumage (Prater et al. 1977). Also, tail feathers are adult patterned, and the bird is a male; specially for the bright underparts.

Why are all this waders orangish in summer? I've been looking for some explanation, but I haven't found anything. As the colour is a deep orange, I guess the phaeomelanin will be the main component of it. I don't think carotenoids would be very related to this colouration...
Also, the tone is more or less the same in very different species, like Knots, Curlew Sandpipers and Godwits. Who knows...

The start of a new season

Another year, another season. I'm back to Faslterbo, where I'll be ringing for two months in the Flommen reedbed. It's already the third season for me here, but all of them are always different.

The first day of the season was specially good. We trapped 102 birds, but the big number was mainly because of the Swallows and Martins. We trapped 62 Sand Martins (Riparia riparia) and 12 Barn Swallows (Hirundo rustica), that were roosting on the reeds in the northern round. It was actually the second biggest catch of Sand Martins ever!!

When I came, Björn told me a dead Bearded Tit (Panurus biarmicus) had been found by the reedbed. It is still very early for migrating Panurus, so it was suggesting a possible breeding in Flommen. During the first day we trapped 2 youngsters, both males, and during the following days, we got 3 more: a total number of 4 juveniles (3 males and 1 female) and 1 adult female, so far.
First year (EURING 3) male.
Sexing juvenile Bearded Tits is rather easy. Female to the
left, male to the right.
Adult (EURING 4) female.
Not all are good news. After talks with different friends, it seems that the breeding season has been really bad for many species. Both May and June were very cold, and there's apparently less insects than other years, specially in the reeds. This feeling is actually noticeable in the ringing totals, cause almost 20% of the Warblers caught were juveniles, and there is apparently many less Reed Warblers (Acrocephalus scirpaceus) in the reedbed.

Indeed, if we don't count the hirundines, we are catching just a few birds. It will be really interesting how the season goes. At least we have trapped a bit of diversity..

First year Yellow Wagtail (Motacilla flava) in complete
juvenile plumage. It looked like a Pipit when I saw it
for first time!
First year Reed Bunting (Emberiza schoeniclus) in juvenile
plumage. They breed in Flommen!
Some are already doing the postnuptial moult...
While some are still very worn...
Like this one, a second year female! Yes, some very worn
females have complete black head and even greyish rump,
but the white collar is narrow, and the bib is not completely
black, just the malar stripes and some random feathers
in the middle.
 In the lighthouse, Caroline and Sophie trapped this young female European Green Woodpecker (Picus viridis viridis), a very nice catch, specially if we look at the totals: the last one was ringed in 1995, and is just the 5th ever!

 It really surprised me how dark and mottled was. I had only seen Iberian Green Woodpeckers (P.v.sharpei) before! Here is a comparation of both subspecies. Also, the one in the bottom is a male: note the red moustache.

We spent one afternoon in Knösen for the bird counts we got very nice views of about 200 Barnacle Geese (Branta leucopsis) feeding.

We are having some windy and rainy days lately, but I still have a very nice feeling for this season.

First sunrise of the new season