Friday, June 13, 2008

2008 catches

May 26th-27th: 28 stormies
May 27th-28th: 20 stormies, 1 carrying a Norwegian ring
May 28th-29th: 58 stormies
May 29th-30th: 23 stormies
May 30th-31st: 33 stormies, 1 Spanish ring
May 31st-June 1st: 34 stormies
June 1st-2nd: Night off
June 2nd-3rd: 14 stormies, 1 UK ring
June 3rd-4th: 10 stormies
June 4th-5th: 30 stormies, 1 UK ring
June 5th-6th, 28 stormies, 1 French ring
June 6th-7th: 32 stormies, 1 UK ring
June 7th-8th: 30 stormies
June 8th-9th: Night off!
June 9th-10th: 2 stormies caught and ringed at sea, 6 nautical miles S of Portimao
June 10th-11th: 102 stormies, 2 UK rings, 1 MADEIRAN PETREL
June 11th-12th: 46 stormies
June 12th-13th: 38 stormies
June 13th-14th: Night off!
June 14th-15th: 21 stormies, 1 UK ring
June 15th-16th: 16 stormies
June 16th-17th: 38 stormies, 1 French ring & 1 Norwegian ring
June 17th-18th: 17 stormies
June 18th-19th: 6 stormies, 1 recapture from the 26th May
June 19th-20th: Night off!
June 20th-21th: 10 stormies

End of 2008 season!

Year total: 636 stormies, 11 controls + 1 Madeiran petrel

On nights in green, the Secret Weapon was deployed.

Thursday, June 12, 2008

The Secret Weapon

Our secret weapon for catching stormies is a small bottle of Dimethyl Sulphide -which is the chemical released when phytoplankton are grazed by zooplankton. Amazingly, the smell of this can be detected by petrels over large distances at sea, and used to home in on patches of high productivity in which larger zooplankton and fish (storm petrel prey) are likely to be found. Whether this actually lures petrels in to our nets is a topic of much debate at Cruzinha -Renata is healthily sceptical while Rob is a True Believer. Only time and an end-of-season stats test will tell us the answer...
The end of season stats were rather ambiguous (there either is, or is not, a Secret Weapon Effect, depending on which stats test one chooses), so we are keen to continue this experiment over the summer, at other points along the migration route. If you are a petreller and would like to take part in this experiment by using the Secret Weapon on 50% of your catching nights, please contact Rob Thomas ( to be sent a bottle of dimethyl sulphate (with accompanying risk assessment).
Thanks to those who have volunteered so far to join in with this experiment:
Bob Harris (Eilan Nan Ron, Scotland)
-Adrian George (Anglesey, Wales / Tyne & Wear, England)
-John Brown (Tyne & Wear, England)
-Declan Clarke (Sheepland, Northern Ireland)
-Kieran Foster (North Wales)
Here are some additional notes on the method:
1. In Portugal, we simply alternated nights with and nights without the dimethyl sulphate scent-lure, to test whether we caught more stormies on nights with the scent-lure in operation.
2. On the long Portuguese summer nights (7 hours of catching), we set up the scent lure at dusk, but further North with much shorter nights it may be worth setting up the scent lure some time before dusk, so that a downwind odour trail is already well established by the time catching begins.
3. In Portugal, we simply took the lid off the container to let the smell drift downwind, but it may be worth experimenting with some sort of absorbent wick, to increase the rate of evaporation.
4. We had the impression that our pot of dimethyl sulphate became less smelly over time, so for the last few nights of our field season we used a fresh bottle. Let us know if you need fresh supplies sent to you!
By way of encouragement, here is a reference suggesting that the secret weapon effect really does work on land, at least in the middle of a Leach's petrel colony!
Nevitt, G.A. & Habermann, K. 2003. Behavioral attraction of Leach’s storm-petrels (Oceanodroma leucorhoa) to dimethyl sulfide. Journal of Experimental Biology 206: 1497-1501.

Wednesday, June 11, 2008

Madeiran storm petrel!

On a very busy first night for team 3, a Madeiran petrel was ringed by some very tired petrellers... here are some photos of a great bird -only the 3rd Madeiran petrel ringed at Almadena in 19 years of ringing stormies.

10th primary growing on both wings
1 tail feather growing
Primary coverts, secondaries & alula all fresh
Active body moult
Wing 156mm
Tarsus 23.1mm
Mass 41.7g