05/01/14 - Lucky 13

Slightly out of date now due to the blog taking a back-seat at the end of last year but see below for a short write up of the cannon net catch of Whooper Swans taken at the end of November.

After missing out on getting a sample of Whoopers last year due to the severe flooding (see below for a reminder of how the extreme weather conditions transformed North Duffield Carrs into one gigantic lake for the majority of the year……)

The river meets the Carrs - 21/01/13  

…we were hopeful that this year would make up for it, and with 70 birds in the favoured field it was looking good, that was until the river came up and flooded the banks the day before, thus changing the pattern of the swans behaviour that we had been monitoring from dawn onwards for the previous seven days.

Like often with cannon net catches it didn’t come off on the morning of the catch, as the swans chose not to come in for an early feed, instead they made the most of the extra space in the river which had burst its banks the day before. After several very cold hours sat waiting the decision was taken to call it a day. Instead a walk on Skipwith Common was had, in search of new fungi species – which saw several new species added to the year list (which finished on a very pleasing 73 species!).

Due to a technical hitch the second attempt was a non-starter and so it was a case of third time lucky – and the last chance for the week with the weather changing and with it bringing strong winds. Luckily everything went in our favour this time, the swans arrived on time, the wind didn’t blow, the net fired and 13 swans were caught.

Amongst them were 12 new birds, 6 of which were youngsters, which is very pleasing as we now hope to match up who's with who.... One darvic’d bird was also re-caught, which has now frequented the LDV for the sixth winter – it was first caught here back in 2007 as an adult. Six years later and he’s still going strong and looking good. See below for the full details of C3S and one other darvic'd bird that has been seen.

C3S:

 

- Ringed as an adult on the 16/11/07 at North Duffield Carrs, staying all winter, and last sighted on the 05/02/08. 

- Re-sighted on the 28/10/08 back in the Lower Derwent Valley for the 2nd winter.

- Sighted on the 26/11/08 at North Cave Wetlands.

- Sighted on the 06/12/08 at Folly Loch, Ancrum, Roxburghshire. 

- Sighted on the 03/01/09 at North Duffield Carrs at the original ringing site. 

- Sighted on the 02/01/10 at North Duffield Carrs and present until 13/03/10 for the third winter.

- Sighted on the 19/12/10 at North Duffield Carrs and present until 12/03/11 for the fourth winter.
- Sighted on the 21/01/13 at North Duffield and present until 11/03/13 for the fifth winter.
- Re-caught on the 28/11/13 at North Duffield Carrs for the sixth winter.

One other darvic'd bird has also been seen in the valley this winter and not for the first time, see below.

Z5T:

- Ringed on the 11/02/11 at the WWT Centre in Caerlaverock, Dumfries, remaining there until at least 02/04/11. 

- Re-sighted on the 16/12/11 at Wester Arboll, Nr Loch Eye, Ross-shire.

- Re-caught on the 29/02/12 at Caerlaverock where it was present from the 07/01/12 until the 20/03/12. 

- Re-sighted on the 21/01/13 at North Duffield Carrs in the  Lower Derwent Valley and present until 11/03/13.
- Re-sighted on the 23/11/13 at North Duffield Carrs in the Lower Derwent Valley.

Prior to this catch 45 Whooper Swans had been ringed in the LDV – now 57. Probably the highest total outside of the WWT centres. Colour-ringing on such large birds is very successful – out of 17 birds caught in a cannon net catch on 30/11/08, 11 have subsequently been re-sighted.

Despite the number of birds in the wintering herd remaining largely similar year on year (peaking at c100), it appears from colour-ringing that the herd may be made up of largely different individuals from one winter to the next. Only a handful of colour-ringed swans have returned to the valley for more than two winters. 

The re-sighting data has also helped gain a better understanding of the use of the LDV by Whoopers – although the peak count of the wintering herd may be in the order of 100 birds, up to 500 individual birds may use or pass though the valley in most winters. There appears to be a passage down the north east of the UK in early autumn before birds arrive in the LDV in November. Some birds continue to the Ouse Washes by December and into the New Year, before birds wintering there start to return to the valley late February/early March. On departure from the valley, some birds return northwards via Caerlaverock and other Scottish sites. 

Many thanks as always to our friends at the WWT for supporting the project and to Robin Ward and Mark Fletcher for the cannon netting. Also thank you to the Yorkshire Post for taking an interest in the story and writing a short piece on the LDV Whoopers - see here.