Monday, October 31, 2016

Autumn migration in the Western Mediterranean

Since I came back from Falsterbo I've been ringing in several places, mainly in my local ringing stations, a ringing weekend in Cap de Creus Natural Park in behalf of CCOW (Cap de Creus October Weekend) and a week in Illa de l'Aire (Menorca) joining on the autumn ringing season organized by SOM (Menorca Ornithological Society).

If I had to underline two impressions from the beginning of October in my area, I would say about the rather abundance of transaharan migrants on 'late' dates (not really late, but rather late in those numbers), since for instance Reed Warblers (Acrocephalus scirpaceus) were present almost anywhere I went (with water nearby)! Also, I had some very good days of migrating Stonechats (Saxicola rubicola), at least significantly better than last 5 years. Quite a good start back to Catalunya!
First year (EURING 3) female Stonechat (Saxicola rubicola)
First year (EURING 3) Reed Warbler (Acrocephalus
During the CCOW, we set up some nets in Jóncols valley, a dense scrubland, with the biggest bushes and scattered trees following a stream (that carried quite a lot of water due to recent rains!). We were ringing in several locations in the Cap de Creus Natural Park, reaching a total number of 1079 birds ringed. Our team was composed by Roger Jutglà, Xevi Rifà, Bet Font, Helena Rifà, Clara Teixidor and me.

The most common species in this area, as migrating birds, are Robins (Erithacus rubecula) and Blackcaps (Sylvia atricapilla). Song Thrushes (Turdus philomelos) are also quite abundant, but apparently not in big numbers as in other places in the Mediterranean coast. Sardinian Warblers (Sylvia melanocephala) are also very common, but most of them might be local birds, since it's very common breeding in this kind of habitat, and most of them had quite extensive moults, including several primaries and/or secondaries. And as it happened in Menorca too, some finches with very extensive moults, like this Goldfinch (Carduelis carduelis) below.

Blackcap (Sylvia atricapilla), the most commonly ringed
species together with Robins.
First year (EURING 3) male Sardinian Warbler (Sylvia
with extensive postjuvenile moult.
First year (EURING 3) Goldfinch (Carduelis carduelis) with
several inner primaries moulted, leaving the three outermost.
This Dartford Warbler (Sylvia undata) was also a nice surprise, probably local too, but we only detected a few individuals around.

What it was not local for sure, and actually wuite a surprise too, was this first-year female Kingfisher (Alcedo atthis) caught while following the stream that runs through the ringing area.

As special, we caught a Blackcap from Belgium and this Yellow-browed Warbler (Phylloscopus inornatus). In total, at least 5 YBW were detected in the Natural Park through the weekend, and more than 50 have been recorded in Catalunya during this autumn...

YBW in the scrubland... Not the place where you would look for them
thinking about suitable habitats, but they can be everywhere!!
Then I moved to Illa de l'Aire, a bit south of Menorca, in the Balearic Islands. The Menorcan Ornithological Society (SOM) runs the standardised autumn ringing season for third year in a row. It's already my fourth time in the island, and first time in autumn. Thank you very much to all who make it possible year by year one more time!!! JJ, Karmele, Romain and me were the ringing team in the Island, with Santi coming for a visit a couple of days. We had a great time!, and a lot of interesting birds...!
A welcoming Shag (Phalacrocorax aristotelis)

As in Cap de Creus, but especially more here, Robins (Erithacus rubecula) are the commonest migrants in the island. Indeed, this year turned out to be a very good season; already at Falsterbo when I was there and in ringing campaings in Catalunya and in the Balearics too.

The season it's been good also for Song Thrushes (Turdus philomelos) and Dunnocks (Prunella modularis), although the latter is caught and seen in few numbers in the island. And sadly, a few Dunnocks were the closest I could get to a Siberian Accentor...

Other Thruses were also seen or caught, like some Redwings (Turdus iliacus) on migration, a Mistle Thrush (Turdus viscivorus) ringed, which was the first ringed in the island during autumn, and quite a lot of migrating Blackbirds (Turdus merula), with days with more than 20 individuals around the island.

The plumage variation in Blackbirds, especially in females, was quite surprising, being these two examples
 two extremes of the observed variation, from very brown with rusty and 'song-thrush-spotted' underparts
(left) to rather dark and uniform plumage (right). Both were first-year (EURING 3) females. Where could they be from?
It has not been the best year for Firecrests (Regulus ignicapilla), but still are rather common migrants on this dates. Goldcrests (Regulus regulus) have been quite rare this season, I haven't seen any actually...
Best birds were a Lesser Whitethroat (Sylvia curruca) and another Yellow-browed Warbler (Phylloscopus inornatus), both rarities but regularly caught in the island; especially curruca, which is caught almost anually in both spring and autumn seasons.
Once the campaign was finished and I was back to my area in central Catalunya, good numbers of both Black Redstarts (Phoenicurus ochruros) and Reed Buntings (Emberiza schoeniclus) were passing.

Visiting almost daily my local patch, it was a nice surprise to find a flock of 10 Penduline Tits (Remiz pendulinus) one day in the evening, that for sure arrived that same day. Minutes after I had a net up to target them, since they are rather scarce in the area and ringing them has provided a lot of interesting recaps between areas, and a rather high rate of foreign recoveries. Indeed, we caught quickly 9 out of 10 Penduline Tits around, since the last one was bouncing on the net but always sneaky enough to scape. This had already happened to my one with an Italian Penduline Tit in the same place, so we extracted the others and left that one alone. In the next round it was caught, and it was actually carrying a French ring!!

Being a first-year (EURING 3) it had to be ringed this same year. The recovery information has been quick (thank you Raül for the quick information flux), and the bird was ringed 13 days before, 435 km away, in Les Iles, Chateauneuf-sur-isere (check map below). It's already the third recap I get in my place from birds from this area between SE France and NW Italy!

Map created using Google Maps
And, as so many Yellow-browed Warblers were being seen everywhere, I was especially motivated to find one in my area. After quite disappointing hours searching in several days and several places, I could hear and see one at the same spot where I saw the last in the area, two years ago
Many sightings in Catalunya have occured in public parks,
like this one in Navarcles village.
It's amazing the amount of YBW seen every autumn for the last years in W
and S Europe, something has to happen...

Sunday, October 2, 2016

Night-ringing at Falsterbo, 2016

Birds can be caught not only during the day, so also during the night. Some groups are actually much easier to trap overnight, some groups as interesting as the waders. And although spend the whole night catching birds can be quite hard while working in an autumn ringing season, we dedicated some effort to catch some birds at Falsterbo.

During the first night we went out for some waders we had quite high sea level, which difficulted putting up the nets on the beach as we usually do. We only could manage to set up two nets on a line, one of them starting from the beach and towards the sea. We caught more than 30 birds, with a nice combination of species, which reminded us that sometimes, even with difficulties (high water levels, wind or whatever), it's worth to give a try!!!

We caught several species in the different ringing nights, such as:

Common Terns (Sterna hirundo)
Sandwich Tern (Sterna sandvicensis)
First-year Common Ringed Plover (Charadrius hiaticula)
First-year Curlew Sandpiper (Calidris ferruginea)
Red Knots (Calidris canutus): adult (EURING 4) above and
first-year (EURING 3) in the bottom. 
Dunlin (Calidris alpina). This individual in particular had a
ring from Ukraine!!
Adult (EURING 6) Sanderling (Calidris alba)
Two subspecies of Common Redshank (Tringa totanus) in the area: the breeding population of the nominate subspecies, Tringa totanus totanus, and the wintering population of Icelandic Redshanks (Tringa totanus robusta). Identification in the field is not easy when both subespecies occur in the area (around September). Measurements are the best criteria (in hand), being robusta larger and much bigger in body size - actually quite different!

Common Redshank (Tringa totanus totanus), first-year
Apart from the size, some plumage characteristics can be useful too. Robusta redshanks are slightly greyer on the underparts, especially in the head and neck, and less striked. Also, tail pattern is slightly different: more espaced, well-defined black lines in robusta. In the picture below, robusta to the right and totanus to the left.

There's certaintly very few information on ageing Bar-tailed Godwits. According to Cramp et al. (1983) in  The Birds of the Western Palearctic, adults have a complete moult usually in winter (sometimes started in summer and arrested during migration), and juveniles have a partial postjuvenile moult. Both adults and first winter individuals have a partial pre-breeding moult too. Therefore, flight feathers in first-cycle birds are not replaced until their first summer.
Up to the 2nd summer (3rd calendar-year) birds are not mature for breeding, and thus some 1st summer (2nd calendar-year) individuals are staying over the summer in the wintering grounds. Nontheless, the rest of second-years are meant to migrate north even they apparenly don't breed.

Even with few birds examined at Falsterbo, it seems like some individuals are clearly more worn and with much more narrow wing-feathers than the others. Pictures and comments below are speculative and based on my opinion, and after reading information from Cramp et al. (1983), Demongin (2016) and Prater et al. (1977) and looking at several pictures on internet.

Rather 'fresh' individual, with wide primary coverts, inner
primaries and secondaries. In my opinion, an adult (EURING 6).
Worn individual, with narrow primary coverts, inner primaries
and secondaries. Probably a second-year (EURING 5).
Comparison of primary coverts wear, shape and pattern (of the
white edge). Adult to the left, second-year to the right.
Comparison of secondaries and greater coverts on wear, shape
and pattern (of the white edges). Adult to the left,
second-year to the right.
Comparison of tail and upper-tail feathers on wear and shape
and pattern (narrower or thicker barring). Adult to the left,
second-year to the right.
Sex determination is based on measurements mainly, especially on bill lenght, which is larger in females (see picture below). Also, males are meant to be brighter orange-coloured in summer plumage (Prater et al. 1977). If you are interested in the subject, I recommend this 'hightly speculative' but very interesting post about Bar-tailed Godwit's bills.
Side by side, it appears to be quite striking! Male to the left,
female to the right.
Oystercatchers (Haematopus ostralegus) are very beautiful birds!! And there's few information about ageing and sexing too... at least that I was able to find.

First-year (EURING 3) to the left, with dark iris colour,
blackish bill tip, greyish legs (not in the picture) and faint
white collar. To the right, an adult, probably 4+cy (EURING 8)
due to bright iris colour and orbital ring, bill and pinkish legs
(not in the picture).
According to Cramp et al. (1983), adults have a complete moult while juveniles have a partial postjuvenile moult. 1st-summer (2nd-year) individuals would undergo a complete moult during summer, so, so far, no known ageing criteria in plumage for second and third winter birds is known, only bare parts colouration, which is meant to change progressively from the juvenile to the 4+cy.
Adult (EURING 8) seen above; whole wing moulted in previous
year, but still rather fresh plumage except for tertials (probably
due to more exposition to wear). Secondaries are wide and with
a white edge on the tip.
First-year (EURING 3) seen above; whole wing fresh. Faint
brownish tips to wing coverts and body feathers, not deep black
as in adults, and narrow secondaries without white edge.
Later on in the season, we go less for wader ringing and more often to catch owls, if it's a good year. I usually leave Falsterbo before good owl ringing nights, so I haven't experienced it properly yet. Anyway, we caught 2 Barnacle Geese (Branta leucopsis) during our first 'owling' night, quite a nice surprise!!