Andorinhas return to the streets of Aveiro

September 29, 2017: 38 birds present at the known roost site in the PM. As if they never left. Discovered there by Davina & Daniel, on a big night out...

Monarch butterflies (Danaus plexippus) in Aveiro, Portugal

These migrants saw the American election results coming and left their continent? I noticed several of these in and around Aveiro daily for the past few weeks, always difficult to photograph.

Andorinhas return

Aveiro, Portugal, October 16, 2016, 20:30.

Dead Razorbills

The Razorbill (Alca torda) is a colonial seabird that only comes to land in order to breed. Or after it died. On February 16 2016, we noticed no fewer than 7 fresh Razorbill carcasses on just under 3 kilometers of tide line at the height of Praia Poço da Cruz and Areao (Aveiro, Portugal). I suspect a period of stormy weather that occurred here a few days ago took its toll and the birds affected were local wintering individuals that reside there not far offshore. I wonder what the situation is on other Portuguese beaches.

Merry christmas and a happy climatic change

The day a new apartment in the centre of Aveiro (Portugal) got occupied (December 1, 2015), a large pre-roost gathering of Barn Swallows (Hirundo rustica) got noticed there, high up in the sky. Barn Swallows are a species assumed to spend the winter in Africa....

Today some big folks signed some deal that would help us all with taking care of climatic change...

Today also, we managed to find the exact roost of the swallows. A total of 150 Barn Swallows was counted, roosting on some small street corner in the centre of Aveiro. On December 12, 2015. A record for Portugal for December? While all other birders in the area were driving around in their cars looking for rarities... None of them recorded a single Barn Swallow this day (or this month?) it seemed...

Merry Christmas and a happy Climatic Change to everybody, anyway...


Tim



Photo by Fabi











Photo by Fabi




Photo by Fabi

Great work on little brown jobs in Salreu, Portugal (September 8 & 9, 2014)

More information and the results of two enjoyable mornings of ringing in the marshes of Salreu with Julio M. Neto can be found here:

September 8: https://sites.google.com/site/juliomneto/blog/alatestart
September 9: https://sites.google.com/site/juliomneto/blog/onemorebritishrecovery





European stonechat Saxicola rubicola







Cetti's warbler Cettia cetti




Common waxbill Estrilda astrild







Bluethroat Luscinia svecica
 



Tree pipit Anthus trivialis







Sedge warbler Acrocephalus schoenobaenus







Weighing a ..?

Gull rings & the Yellow-legged Gull (Larus michahellis) as probable breeder in Aveiro, Portugal

Yellow-legged Gull PFFF, ringed in Spain, observed at the Porto de pesca (photo: Pedro Moreira)

 
On August 28 Pedro Moreira and I went out to search for colour-ringed gulls in the area around Aveiro, Portugal. Our day started at the Eirol landfill, where usually good numbers of gulls are present, especially now that fall migration has started. However, the number of gulls there turned out to be a bit disappointing. We made a very rough estimation of about 3500 Lesser Black-backed, 150 Yellow-legged and 20 Black-headed Gulls; similar numbers as on our visit to the site of August 21. Unfortunately, most of these birds perched on the roofs of the buildings, making it difficult to read their rings. There were moments when the whole pit remained empty from gulls. Only 35 rings were read (fewer than last time). Around noon we decided to leave the place and find out where our birds had gone to.

An empty landfill

We passed by the beaches to see if bycatch from Xavega (the traditional fishing where the catch is landed on the beach, see Paul Veron's blog entry about this event: http://guernseygulls.blogspot.pt/2014/08/the-exodus-of-lbbgs.html) was attracting them. But as the waves were too high that day (as on the previous days), there were only few gulls present, all of which were flying over the ocean. Better luck we had at ‘Porto de Pesca’, the largest fishing harbour in the area. Roughly 1500 Lesser Black-backed Gulls were present there, allowing us to read 8 rings on those. Besides these Lesser Black-backed Gulls, about 400 Yellow-legged Gulls were present in the harbour. Of these at least 5 were ringed.

Lesser Black-backed Gull 'E4', at Porto de Pesca. Ringed in the SW of the Netherlands (photo: Pedro Moreira)

 

 

 

Yellow-legged Gull N:1NC, from Spain, observed at the Porto de Pesca (photo: Pedro Moreira)

Yellow-legged Gull 1Y5 at the Porto de Pesca; note the worn and open colour-ring, about to fall off (photo: Pedro Moreira)

Some of these Yellow-legged Gulls, all adult birds, have been seen at the harbour earlier this summer. Apparently the seaport to Aveiro is attractive for this species. With many expanding breeding populations in nearby areas (i.e. Porto), it would be just a matter of time before they start nesting here (assuming that they didn’t do this already). And indeed, we found information that by now Yellow-legged Gulls nest in the harbour!

While searching for rings we noticed two immature Yellow-legged Gulls begging at two adults, which were involved in some kind of social conflict with a third adult bird. With the appearance of our car, the adults started to alarm. Both chicks were able to fly properly and could be considered fledged.

Two begging Yellow-legged Gull chicks and their presumed parents (photo: Pedro Moreira)

Of course, observations of begging but fledged gull chicks are by no means good evidence that the chicks were born in the area, as they are capable of following their parents over long distances. However, our suspicion that these were in fact local birds gets supported by the following information I received from Pedro.

The same begging Yellow-legged Gull chicks and their presumed parents (involved in social interactions with a third bird)

On August 8 Pedro visited the harbour to read rings and talked there with a fisherman, very close to the particular location. He was told “You are late! You should have come earlier to see the nest!”. Apparently there had been a nest on the dock on a rolled up rope, containing three eggs. Out of these two chicks hatched. It was the first time the fishermen had seen it there. When Pedro approached the location of the nest he got dive-bombed by an adult Yellow-legged Gull. A bit further away he saw a young juvenile (about the same in size as the ones on the photos above). Then Pedro realized he had been dive-bombed at the same location earlier in the summer, on July 17. He never saw the nest but never looked for it either. At inspection of the location on August 28 we did not find any remains of any nest, but by that time it would have been washed away by the elements. It seems probable that the two chicks we observed belonged to this nest.

It would be interesting to see how in the future the migrant and wintering population of Lesser Black-backed Gulls in this part of the world is going to deal with an increasing Yellow-legged Gull population, since competition for food between the two species can be expected. If you happen to know more about nesting gulls in or near Aveiro (and this would not be the first nesting of the Yellow-legged in the area) I would be very interested in this information.

After this encounter, we headed to the Porto de Commercial, where during the high tide a large parking place gets used by the gulls as a roost. 2000 Lesser Black-backed, 500 Yellow-legged and one Greater Black-backed Gull were present. 8 rings were read.

Part of the large gull-roost at the Porto de Commercial, Aveiro

This number of gulls however did not explain where many of the gulls had gone to (we still had the impression we were missing many). It may be possible that some of the recently arrived Lesser Black-backed Gulls found a better place at the larger fishing harbours in i.e. Leixoeis or Figueira da Foz, where the larger fishing boats arrive, which are better at dealing with the waves.

Subadult Greater Black-backed Gull Larus marinus (photo: Pedro Moreira)

And now for something completely different?

While walking in Parque da Fontenova in Aveiro (Portugal) on February 25, my I caught a somewhat strange white bird among several Black-headed Gulls that were foraging on the grass. At closer inspection it appeared it was also a Black-headed Gull, but with a colouring defect in its wings (http://observado.org/waarneming/view/81965799). Unfortunately, I wasn’t carrying a camera. Today March 1 the dogs got a walk in the same park and also the gull appeared there again. Coincidentally I ran into Pedro Moreira, who luckily brought his camera with him as he was already on the lookout for this particular bird. Pedro sent me the following photos.

Partially leucistic Black headed Gull Parque da Fontenova in Aveiro, Portugal. March 1, 2013 (photos by Pedro Moreira).

As far as defects in colouring go, this type of deviation seems to occur more regularly among this species. See i.e. http://www.frankmajoor.nl/kokmeeuwen-kleurafwijkingen-1-nl.shtml. Not as completely different as I first thought, but still a beautiful bird to see.

Gull die-off in the Ria de Aveiro

Once a week the dog gets a walk along the a few hundred meter long sand dam on the Ria de Aveiro, at the height of the University of Aveiro. On this walk I identify and count fresh carcasses of birds (and once a feral cat). About three weeks ago I started to notice a rapid increase of dead Lesser Black-backed Gulls and Black-headed Gulls. I usually find (depending on the time of the year and the number of gulls present in the area) about 0-1 gull carcass on each trip. Within the past three weeks I found there the carcasses of 10 LBBG (9 adult and 1 immature) and 4 adult BHG. About two weeks ago I spoke with 'Ines', a UA student who also walks with Juli along the Ria at the height of the university. At that time she told me Juli ran onto the mudflats while chasing a dark gull that could not fly. On October 3 I got informed by an inhabitant of Sao Jacinto that he had noticed an unusual high number of deceased and dying LBBG out on the most southern dam of the peninsula, about 7 kilometers from the earlier location. He told me he found 21 gulls of which a few were still alive. These live birds were unable to walk and were turning their heads backwards in an odd way. Today Flor and I walked our transect again and ran into this adult LBBG showing symptoms of poisoning. About 40 meters from us was another adult LBBG present on the water surface which appeared to be trying to fly, though it did not manage. There were no new carcasses present on the transect, but the recent high tide could have swept away most of the dead matter. I regularly count the number of live LBBG and BHG present at this part of the Ria, which, during today’s upcoming tide, was surprisingly low, compared to earlier high tide visits. I have informed Biology student 'João' from the University of Aveiro about this situation in the hopes that the situation can be investigated. Luis would inform his supervisors about this, what seems to be fair to call, gull die-off in the Ria de Aveiro.

Back in Aveiro...

Where spring is already in the air... Many White Storks Ciconia ciconia (like these ones today near Pardilhó) are now reconstructing their nest, as many had been blown away by a recent storm that lasted multiple days and took out many trees in the area as well. 

A final batch of gull ring readings from the Taboeira landfill…

Ok, I realize that I’ve announced the closing of the Taboeira landfill far too often on this blog, but this will ‘probably definitely’ be my last entry about the site. In the previous entry you could read that gull numbers out there apparently had increased recently, and I will explain here in detail what has happened.

On my last few visits to the site the number of gulls was reasonable (8-9000 birds by the end of August, increasing to about 10.000 – 11.000 birds on my last visit on September 7), but with a notably decreasing amount of waste being transported to the site I suspected that things would be over soon for the gaivotas. When passing the official closing date of October 8, I believed no gull would set foot on Taboeira anymore and today personnel informed me that about a week ago not a single gull was present at the site. Around the same time it became obvious that gull numbers around Aveiro had dropped notably.

After the valuable tip I received last Saturday about the high number of gulls that currently can be found at the landfill, I figured this could be my last chance to get some serious gull-ring resightings. The saltpans and mudflats certainly are a nice place to work, but the number of gulls with readable rings there are only a fraction of what can be found at Taboeira, within the same amount of time.

So, this morning I got up early for ‘The Final Taboeira Visit’. However, while on my way I noticed something strange… A rather large number of gulls was flying over me, coming from the west (from roost sites in the Ria) and heading to the southeast… This appeared to be a bit odd; as long as we live here in Aveiro the gulls from the Ria travel northeast to get to Taboeira in the morning, and fly back to the southwest by the end of the day. At that point I highly suspected that a large number of gulls by now have found their way to the new landfill site (Eirol)...

Commuting gull routes in the early morning of October 29 2012: Black arrows are flight paths, red line is the road to Taboeira (small light blue circle) and Eirol is the larger dark blue circle. Only from about 2 km from Taboeira did I notice gulls flying to the original site.

At arrival at Taboeira at 7:00 there was a very good number of gulls present (around 20.000), which reminded me of the hay days of the site (but double this number to get to the best days in December 2011 – February 2012). It turned out that even though the site had stopped accepting waste since October 8, a certain amount of waste is being imported from the new site in Eirol, in order to be able to level off the last mound, before it will be covered up with soil completely in only a few days from now. And then the gulls will be gone.

 

During the following 5 hours I managed to read 35 rings, including 33 Lesser Black-backed Gulls and 2 Black-headed gulls, and these were applied in Britain (12) The Netherlands (8), Guernsey (6), Germany (3), Denmark (2), Norway (1), France (1), Belgium (1) and Poland (1). The number of rings read could have been a lot higher, but I decided to take the opportunity to chat up with several of the site’s personnel on this final visit. They’re all very nice people out there, and ERSUC has been very supportive during my visits. Thank you all!

 Oh, yeah, gull rings... Peter Rock's BLUE T+U, WHITE inscription, from...around Bristol, UK?

 Black-headed Gulls were common in the winter at Taboeira, but they allways got totally outnumbered by the LBBG; today about 1000 of 'm were present, including this WHITE 521, BLACK inscription from Denmark. Today another BHG carried a ring from Poland.

A new bird on the site? LBBG adult; GREEN Y.AKU, WHITE inscription, ringed as an adult by the Cottaar-Verbeek ringteam in 2009 at the 'Forteiland' in IJmuiden, The Netherlands. The bird has only one other record outside of the Netherlands (Belgium, Zeebrugge beach, October 8 2010). 

One of the employees gave me this LBBG(?) leg with a Brussels’ metal ring which he found some time ago. I passed it on to Eric Stienen (Belgium) who will do the paperwork, I hope.