Survey of beached birds and mammals: São Jacinto – Torreira, Portugal. March 27, 2014

British-ringed Atlantic Puffin

Yet unidentified dolphin

Picking up Puffins on the first beached bird and mammal survey between Sao Jacinto and Torreira

On March 14 2014, a survey of beached birds and mammals was conducted along a 10 km long transect between Sao Jacinto and Torreira, by Pedro Moreira and me. The transect included 5 km of closed off beach belonging to the Sao Jacinto reserve, who gave us permission for this survey. The idea was to get an impression of what species and their numbers had been washing up on the beach along the northwestern coastline of Portugal during the previous months. None of this 10 km of beach gets regularly cleaned, making it a very suitable length of coastline for this study.

Another motivation for this activity had been the reports of large numbers of dead seabirds that washed up on beaches in France and Spain, after the ‘wreck’ that occurred earlier in the year in the Bay of Biscay due to continuing bad weather conditions (See http://www.sott.net/article/274701-Update-Tens-of-thousands-of-dead-seabirds-have-now-washed-up-in-Bay-of-Biscay and http://www.timvannus.blogspot.nl/2014/03/dead-british-seabirds-are-finding-their.html).

 The 10 km transect we walked from Sao Jacinto to Torreira.

Results

Which of these birds died in the wreck that occurred in the beginning of the year remains difficult to determine, with the absence of earlier survey results. We suspect this had been the case with all of the puffins that were found. Even the few of those that we found on the recent tide lines showed signs these had been floating in the ocean for a while. All of the Lesser Black-backed Gulls had died recently and these were probably all local birds. Also the Common Guillemot and one or two Razorbills appeared a bit too fresh to have come all the way from the Bay of Biscay.

Beached Atlantic Puffins.

 

 Three Lesser Black-backed Gulls and two Razorbills.

 Great Northern Loon.

Unidentified Seahorse...

...and a coconut.

Dead British seabirds are finding their way to Portuguese beaches?

A survey of stranded seabirds on the Atlantic coast of France has found more than 21,000 of their corpses washed up on shores between Brittany and Spain.

A co-ordinated count that took place last weekend (22-23 February) from Finistère to the Spanish border resulted in 21,341 dead birds begin retrieved, along with and another 2,784 brought to veterinary centres to aid recovery. Several thousand dead seabirds were already counted earlier in the month and fishermen and other boat users reported that there were "carpets of dead birds" still floating at sea.

See http://www.sott.net/article/274701-Update-Tens-of-thousands-of-dead-seabirds-have-now-washed-up-in-Bay-of-Biscay

Today on only a short walk on the beach near Praya de Mira (< 1 km) we found these two Puffins Fratercula arctica and one Black-legged Kittiwake Rissa tridactyla.

Fratercula arctica; but where did its wing feathers go to? I assume it has not been marked by someone.

 Rissa tridactyla.

No die-off yet.., just many dead gulls

In response to my announcement of a ‘gull die-off’, Professor Antonio Luis (University of Aveiro) informed me that this part of the Ria de Aveiro is part of a very wide basin, which has several industrial areas, agriculture, cattle, etc. The road network is relatively dense too. It's also known that the lagoon itself is very polluted at some points, from very local sources. On the other hand these were the first rains in a long time, there were lots of wildfires during summer and now there's nothing to hold both the rain water and the burned ground (as well as what's in it). As a consequence everything is easily washed away, down into the lagoon and flood plains. In summer, when the water gets warmer, it's also common to have toxin blooms (shellfish capture is not allowed during these periods) and these maybe nasty toxins sometimes... The number of possible causes may be pretty big.

In order to investigate the true scale of this thing, and whether we’re experiencing a true die-off or not (in which the population undergoes a sharp decline), during yesterdays afternoon I walked 2 km on and along the shoreline and sand dams of the Ria de Aveiro, near the UA. This track included the 300 m transect I mentioned earlier.

On this track I found the remains of a total of 25 Lesser Black-backed Gulls, 5 Black-headed Gulls and one Common Redshank. Most of the LBBG carcasses were old (17 >multiple weeks/months/a year), one was fresh (the affected live adult that I found on October 6) and 7 probably died within the past three weeks. Most (at least 20) of these were adult plumage birds. Of the BHG carcasses (all adults), one was older than months and 4 had died during the past few weeks. I suspect this has been a slight undercount as not all of the tide line was accessible (about 20% remained unchecked). I found one possibly affected live bird, a solitary adult LBBG in the active salinas, which I could not approach. None of the carcasses I checked was marked.

 

 Older, subadult LBBG carcass

At the salinas and in the Ria there were about 450 LBBG and 170 BHG roosting. Later, at dusk, came roughly 900 LBBG and some BHG over my head from the direction of the local landfill, of which a varying number roosts in this part of the Ria.

This would indicate that the scale of whatever is/was going on seems indeed not to be alarmingly large, at least not in this (relatively isolated) part of the Ria, and no immediate action needs to be taken. Just to be sure, next time I’ll try to investigate a slightly more northern area to see how the situation is there (closer to the ocean's entrance, where several dying gulls had been reported earlier). Let’s hope that whatever this is or was has come to a halt by now, as these dying gulls always are a nasty sight. Considering the scale of this event I am very sure that there will be at least some marked individuals among the recently deceased birds. I will try to keep an eye out for those and recommend local readers of this blog to do the same.

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.