No Luck Catching Them Swans Then.......

There are several hundred Whooper Swans in front of you on a lake. Your task is to catch as many of them as you can. How would you do it?

Swans being herded in the swan pipe

Well thankfully for you, the team at the Wildfowl and Wetlands Trust have perfected the art of swan catching. In one corner of the lake there is a netted tunnel, it is this that you will catch the swans in. There are about 20 people waiting out of site in the wings waiting for the moment when the trap is sprung. One of the site warden walk along the side of the lake doing the daily swan feed, he goes into the pipe, and the birds duly follow. The seconds creep by as you wait for more and more swans to go into the pipe, at the right moment the decision is made, a rope is pulled and the netted door falls down, trapping the swans. You and the other sprint out into the tunnel as fast as you can. You farm a line and slowly walk down the tunnel pushing all the swans into the holding area at the far end, A few try to make a break for it between your legs but they are turned around. The swans all get herded into the pens and the door is closed. Congratulations, you have just completed a successful swan catch.



A swan in a swan harness

This exact scenario was played out twice a couple weeks ago at WWT Caerlaverock in Dumfriesshire and WWT Martin Mere in Lancashire. In total we caught 193 Whooper Swans, 37 Mute Swans, 1 Teal, 1 Pochard, 7 Pintail, 15 Mallard, 15 Shelduck and 7 Coot.

But why did we catch them? Well all the birds caught were fitted with a metal ring and the Whooper Swans and Coot were also given a coloured Darvic ring. This forms a vital part of WWT's long term monitoring program.



Darvic Rings

In addition to being ringed the swans also have a variety of biometric data taken. This helps to assess the swans general condition and health. So once they have been ushered into the holding areas the swans are divided up into a series of smaller pens, this means the catch can be manged better and gives the swans’ adequate room. Swans are then individually caught and sexed, this is done by looking at their vent. Once they have been sexed they are placed in a special designed harness which stops them from struggling.

From here they are passed along onto the ringing table where, unsurprisingly, the rings are fitted. Each bird is given a metal ring with a unique code on it, part of the BTO ringing scheme. The plastic Darvic ring, fitted on the other leg, has a three digit alpha-numeric code on a coloured background. This allows individual birds to be easily identified in the field, without need for re-capture. Here the total head measurement is taken (measuring the beak and skull length) and the tarsus (the lower leg) is measured. The bird is then taken to be weighed and wing length measured, these are carried out by separate teams forming a processing line for the birds. Once all these measurement have been taken the swans are released none the worse for wear. The other species were all fitted with a metal ring.



A map of the breeding a wintering range
of the Whooper Swan

Ringing the swans allows us to track their movements between the wintering grounds in the U.K and the Icelandic breeding grounds. We can also learn how they use different habitats, their lifespan and the partners and offspring. This provides us with invaluable information on their lives and a vital tool for conserving both the swans and their habitats. One a slightly darker note, we also know that 13% of Whooper Swans have lead shot in them, despite having legal protection and that many swans die from ingesting lead form the environment.  From ringing birds in this way we have learnt that some swans can survive to almost thirty years old. Also interestingly, some swans can get blown off course and join the Fennoscandia populations for a short time during winter before coming back the U.K and then returning to Iceland the following spring.  

Also of interest, one of the Pintails was a re-captured bird that was ringed at WWT Slimbridge in 2007.

To find out more about WWT’s work on the Whooper Swan click here.

To sign a petition calling for a ban on the use of lead shot click here.

For more information about bird ringing and the science it underpins click here.