Roseate Tern Question (1 Viewer)

[phyllosc]

Can anyone tell me, why are Roseate Terns rung with a metal ring on each leg? I've heard said that it is BTO policy, but it seems a little strange.

Dave C

 

[Mark Grantham]

All Roseate Terns will carry a normal BTO metal ring, and the second ring is really the equivalent of a colour ring. This second ring normally has two digits (which often represent the BTO ring sequence) above two digits (which represent the last two digits of the metal ring). As these have fewer digits and no return address they are easier to read in the field.

This isn't BTO policy per se, but the project is approved by BTO, as are all other colour ring projects.

Mark Grantham
BTO Ringing Scheme

 

[phyllosc]

Thank you Graham. I can see the logic but anyone would still need to be quite close to read the numbers. I would have thought conventional colour ringing would be more effective. In terms of recovery rates is this double ring sceme as effective as colour ringing?

Dave C

 

[Mark Grantham]

Not sure of the rates, but it has a long history... Most of the rings are read in colonies anyway, which is sufficient for the needs of the research.

Mark G