Sunday, April 17, 2016

Aquatic work

The last two months I have been ringing mostly in fluvial habitats and wetlands, pushing my waders to destruction! And I've got almost no time to write... Hope I can find some time from now on.

From the end of February to mid-March I focused to catch Water Pipits (Anthus spinoletta) in one of my local ringing sites in Central Catalunya.

Adult (EURING 6) Water Pipit (Anthus spinoletta)
2nd-year (EURING 5)
Grey Wagtails (Motacilla cinerea) are common in the area, and I trapped a few as well.

Adult (EURING 6) male Grey Wagtail (Motacilla cinerea)
2nd-year (EURING 5) female
On the other hand, White Wagtails (Motacilla alba) seem to be a bit clever, and I've only got one despite being one of the commonest passerines in the trapping area!
Adult (EURING 6) female White Wagtail (Motacilla alba)
Other interesting stuff were this Green Sandpiper (Tringa ochropus), an adult (EURING 6):


And this 2nd-year (EURING 5) Crag Martin (Ptyonoprogne rupestris). Compare with the adult (EURING 6) trapped last year in spring, in the picture below.

2nd-year (EURING 5) Crag Martin (Ptyonoprogne rupestris)
Adult (EURING 6). Notice the lack of pale fringes in GCs
and tertials, plus the darker colour.
The 1st of April, friends ringing in the Balearics told me they got 5 Wood Warblers (Phylloscopus sibilatrix) early in the morning. We were surprised about the dates, quite early for this species, and we guessed that maybe it was going to be a very good spring for this species like last year was. I got even more convinced about this when I found one in the next netround!, but finally it's been a normal spring, nothing to see with last year. Probably, something happened that night between 31st March and 1st April...


Bluethroat (Luscinia svecica) season it's been good in my area. As expected, all cyanecula...

Adult (EURING 6) female
2nd-year (EURING 5) male
2nd-year (EURING 5) male
2nd-year (EURING 5) male
2nd-year (EURING 5) male
2nd-year (EURING 5) male
Most male cyanecula show an obvious white spot, but a few
males can have this orange-tinged spot. Still, the base of
those feathers is white.
But on a weekend ringing at Aiguamolls de l'Empordà (NE Catalunya) I trapped this short-winged Bluethroat...

I went quickly to measure it: wing chord= 72mm, tail length= 50 mm. Being an adult (EURING 6) female, wing measurement it's just on the top limit for namnetum, but given the tail length plus the very short primary projection, it seems like a very good candidate!
Compare the size and primary projection between namnetum (left) and cyanecula (right).
Adult (EURING 6) female Luscinia svecica namnetum
It's interesting to notice also the amount of blue, and the wide and quite well-defined white spot; that fit with the age but may have some relation with the subspecies (at least the size of the white spot does!).

The main target that weekend was Aquatic Warbler (Acrocephalus paludicola), and we succeded!!

The weekend also produced 3 Bitterns (Botaurus stellaris) and a Baillon's Crake (Porzana pusilla) plus several Spotted Crakes (Porzana porzana) singing around.
Ah, by the way, I have a new pair of waders to 'destroy'!

Thursday, February 25, 2016

Long-tailed Tit subspecies in the Iberian Peninsula

There are two Long-tailed Tit (Aegithalos caudatus) subspecies in the Iberian Peninsula: A.c.taiti and A.c.irbii. The first occurs in central, North and Western Spain and Southern France, while the latter ocurs in Central and Eastern Spain (including most of Portugal). Iberian subspecies distribution is not fully studied, at least as long as I have been able to find in the literature, and some hybridization areas may occur.

Pinkish colours are restricted to undertail coverts and belly,
with rather uniform grey on upperparts. Andalusia, South Spain,
December. A.c.irbii.
A.c.irbii to the left, A.c.taiti to the right.
Check how darker is irbii on cheeks, and how the black stripe
almost reaches bill base.
Apart from the local, sedentary subspecies, there's no information of any foreig retrap in Catalunya (source: www.sioc.cat), neither in the whole Spanish ringing scheme (source: www.anillamientoseo.org). There's only the recovery of a Long-tailed Tit ringed in Spain and recovered in France, but no detailed information. The most likely scenario is that it will be a bird ringed close to the French border and recovered on the other side (?). No other references of foreign birds/subspecies in Spain have been found; and actually, apart from the striking White-headed Long-tailed Tit subspecies (A.c.caudatus), subspecies identification can be very tricky outside of the known distribution range.

 On January I trapped a very striking Long-tailed Tit that attracted my attention since I saw it for first time. I have trapped quite a lot of local birds around Catalunya, and I had never seen any individual similar: very clean white underparts and cheeks and extensive white patch in crown and forehead. In the same net I was lucky enough to catch a local individual, retrap, that was very useful to compare.

The "whitish" bird above, the local individual below.
And that is what happened when I put them together...
  A.c.caudatus can be quickly ruled out on plumage features, but what about europaeus?
Checking pictures during the breeding season taken in the breeding range of europaeus, all individuals fit with the features shown by the bird I trapped: extensive white crown, wide white forehead, whitish ("clean") cheeks and underparts...

The presumed europaeus (left) had appearently a stronger bill
than a normal taiti; although I couldn't take proper measurements,
it's so small anyway!
A.c.europaeus, picture by Emil Lundahl taken in Falsterbo
peninsula, Sweden. Note the very clean white underparts,
as the extensive white on crown and forehead and clean cheeks.
A.c.europaeus, picture by Emil Lundahl taken in Falsterbo
peninsula, Sweden. Note the clean underparts and very clean,
'open-faced'.

Looking to local breeders in other places in Catalunya, especially breeding birds in the Pyrenees, there're no obvious differences with breeding individuals in other places.

Local individual trapped in central Catalonia, age EURING 6
(because it was a retrap from 2013). A.c.taiti.
Wear was for sure not the cause of the whitish plumage, as worn
birds turn to be greyer overall. Breeding individual in central
Catalonia, June. A.c.taiti.
Local breeder in Pyrenees, ringed in July and recaught in
winter. Plumage features fit will all other breeders I have
seen in Catalunya. A.c.taiti.
Despite all of this, only DNA analyses could confirm for sure the subspecies identification... but in the meanwhile, keep looking at the Long-tailed Tits!

Saturday, February 20, 2016

Gallocanta

I think February is quite a good time for this short trip to Gallocanta and surroundings. Cranes (Grus grus) invade Gallocanta lagoon every winter in flocks of thousands; they eat on the field around the area and they come, at dusk, to sleep on the laggon. That is an scenario that I truly recommend to everybody.
Around the lagoon there's an extense area of low reedbeds, grasslands and drylands. Hen Harriers (Circus cyaneus) are also very common, flying around trying to catch some Calandra Larks (Melanocorypha calandra), Skylarks (Alauda arvensis) or Corn Buntings (Emberiza calandra), three of the commonest passerine species in the area.

I was preety enthusiastic about the few Iberian hares (Lepus granatensis) we saw, I had only seen europaeus so far and they actually look very different!
If you are lucky you can also get to see a flock of Black-bellied Sandgrouses (Pterocles orientalis), a rather endangered species in Catalunya, especially for habitat loss, but still with good areas in Aragón.

Back to the Cranes, the moult strategy is something that has kept me always interested about. It is well known that many non-passerines species have very different moult strategies rather than the usual passerine strategies. In the Eurasian Crane (Grus grus), the postjuvenile moult is partial, and involves some head, neck and body feathers. Thus, ageing first-winter individuals in the field is quite easy: they still have many juvenile feathers.

Two first-winters. Still amny juvenile feathers; head, neck and tertials are striking.
'Advanced' first-winter, the second starting from the right. Still easy to age
from the distance.
Rufous head is particularly useful in flight!
Cramp et al. (1979) also says first-winters have a winter moult, between December and May, which is partial, and also involves head and neck and some body feathers, tertials and upper wing coverts. Then, after their first summer and to the second winter, individuals can still be aged on the juvenile primaries (not moulted yet) and, as they moult slowly, they tend to have more retained feathers in head, neck and body than adults. It is estimated that flight feathers are moulted for first time on the 3rd summer, although some birds started it in the 4rth. After that moult, adults replace flight feathers every 2 to 4 years, depending on different factors like breeding success. The flight feather's moult is simultaneous, like Wildfowl, and it takes a period of a few weeks being flightless. Some strategies for the flightless period are suggested, from moulting at the same time as breeding (already with running chicks) to Cranes reported moulting while hidden in a reedbed.

Adults
Notice the difference in wear in the two adults below. The bird on the left shows no retained head, neck, body feathers, neither wing coverts (except for primary coverts), which suggest it is an adult that has been carrying the same flight feathers for some seasons!

  
Later on, I was surprised when I saw this adult in apparent secondary moult, but I guessed it was hurt or something. But when it flew, and as you can see below, it was actually moulting secondaries!! At least the gaps in both wings seems of the same size (involving the same feathers). Primaries look new (compare with the bird flying behind, which is the same commented above), and grown secondaries also look pretty new. An adult that started flight feathers moult and that suspended after finishing primary moult, and continued in the wintering grounds?? Maybe a moulting bird in the area that is not flightless anymore, but still hasn't finished the moult?


A trip to Aragón in winter deserves a visit to Gallocanta, but also to Belchite steppes. We had the chance to hear, and rather close, up to 5 Dupont's Larks (Chersophilus duponti) singing at dusk. For those interested in going there, remember to be respectful: Dupont's Lark is a really endangered species, especially because it is very sensitive to disturbance and habitat loss.


But as I was saying, and especially if you haven't gone yet, Gallocanta is a must-see for next winter!