pt-ducks update and celebrating 20 years of waterfowl capture and marking in Portugal
Long time since my last post about this...
Regarding last season update, the news aren’t the best since for the first time in 10 years we didn’t managed to reach 1000 birds captured… :-C
I had decided to reduce capture effort in order to increase resighting effort – I was planning to do only one day of captures (instead of 2), each time I would go to S. Jacinto and use that extra day for extra resighting. However captures were reduced during autumn (none day with more than 100 new ducks...), so did 2 days capture as usual, although only went once a month to S. Jacinto, from October to December – no formal project, neither funding for field expenses…
As during previous winters, the resident pair of
Accipiter gentilis continued to flush migratory ducks from the main pond to a secondary pond where we don’t do captures, at S. Jacinto, but the worst happened on mid-January when a big storm, like a hurricane, occurred in central Portugal, with very strong winds and heavy rain that destroyed many trees at S. Jacinto, flushed most ducks from the site and flooded Mondego lowlands… A big willow felt over the net roof of the big trap and we passed the remaining winter (thanks Tim!) and early summer cutting trees that felt down and repairing the big trap. However we managed to end the season with more than 20.000 birds captured although not reached 18.000 ducks nasal saddled, even trying to force it…
The EVOA project lagoons showed me that you need more then lots of ducks (8500 teals... see video at
http://www.pt-ducks.com/Fotos.htm#Tejo – choose full screen, full HD and increase volume!), knowledge on how to capture ducks and loads of experience of doing it, to have success on captures. As it was a new place where I only could go few times, there were loads of ducks and I wanted to minimize disturbance, I went by the safest way and didn't managed to capture any duck during winter – tried 4 times... During the summer of 2013 I "learned" the place, had the help of Luís Arede doing his degree thesis there and captures started, including teals during September!...
On 18-09-1993 I captured my first ducks at S. Jacinto! On Mondego I started on July 1993 but the really “fun” started at S. Jacinto and if wasn’t this area I probably would stop captures long ago… On the other side, if EVOA existed in 1993, I probably never would start captures at S. Jacinto – yes the potential is so big!
Some curiosities from the 20 year results:
- the oldest duck that we obtained until now died during the season 2012-13. It was a male mallard marked at S. Jacinto on 29-09-1998, as juvenile, and was observed until 19-07-2012, already wearing the second nasal saddle… During May of this year we found his head bones still with the saddle, so lived at least 14 years!;
- the bigger movement obtained was from a male wigeon marked in S. Jacinto and shot in Siberia – Russia, at 5392 km;
- the duck that flew the biggest distance was another male wigeon, also marked at S. Jacinto, that was photographed near a holidays home in a Finish lake, at 3162 km. As it returned to S. Jacinto the following 8 winters, it flew more than 53750km!
From the more important results I can select:
- we managed to estimate monthly survival rates for mallard at S. Jacinto and found that adult females had significantly lower survival rates than adult males, because >50% of adult females were or still had to do primary at 15 August (when traditionally duck hunting started al Portugal). Locally we managed to delay the start of duck hunting to around 7 September and adult female survival during the first hunting month increased almost 20%. At national level we managed to implement this during two hunting seasons but after politicians ruined the ongoing process. I’m still fighting to implement adaptive management at S. Jacinto area, all stake holders agree with the idea but still didn’t found the needed funding…;
- we proved that lead poisoning is also a serious problem in Portugal, reached an agreement with all stake holders on December 2006 but politicians didn’t managed to publish the needed laws until now, although during last 3 years there is a pseudo lead ban “to EU to see”,…;
- we found wigeons and teals moulting primaries in Portugal, so site management must be adapted. On EVOA we already found teals moulting this month, confirming my suspicious since 2 years ago.
Publications references can be found at pt-ducks and also at
http://www.esac.pt/AvesAquaticasCinegeticas/Publicacoes.htm but we have loads of data to publish – hope next years will be better on this…
Captures, Duck Course, Fotos (feel free to use the small videos under CC conditions), and cr-telescopes were updated. Interesting to note that 20 years ago I started with a Nikon ED60 with a 20-45x zoom and nowadays I usually use my telescope combo equivalent to a 41-124x 100º AFOV zoom and can also use a 53-178x 102º AFOV zoom equivalent, when higher resolutions are needed and it works well...