Tallaght Gulls + Rings: The MUTE SWAN projects in 2016

Tuesday, 29 March 2016

The MUTE SWAN projects in 2016

This year we will be looking at 4 aspects of the Mute Swans within the survey area.

· We will be conducting another Mute Swan Nesting Census. Following on from the very successful census in 2015 we will be counting nests and looking at outcome. (I and others have our BTO and NPWS nest recording license and we will also be recording and submitting nest records).
· Cygnet survival and dispersal. With about 50 of the 2015 Cygnets coloured ringed, we can obtain survival data annually and continue to look at dispersal
· We hope to conduct a census and count the number of Swans in June. This is when the majority of Swans are moulting and movement between sites should be at it’s lowest.
· We are commencing a Mute Swan RAS on April 1st

Nesting Swans. Photo taken from 50m away!

A MUTE SWAN RAS

What is it and why?

When collecting and looking at data it is necessary that it is comparable to something historical or contemporary. We are going to use the RAS criteria for this purpose.

Retrap Adults for Survival (RAS)

The Retrap Adults for Survival (RAS) scheme is a national standardised ringing programme within the BTO Ringing Scheme. Within Ireland, England, Wales, Scotland and Northern Ireland, there are currently only 3 Mute Swan RAS projects and none of them are in Ireland.

In a RAS project, ringers aim to catch or re-sight at least 50 adult birds of a single species in a study area during the breeding season. In our case it will be April 1st to September 30th. (As we have coloured Ringed 100+ adults we will be using re-sightings). The study area is defined and we are aiming to record the vast majority of the adults. All sightings of our coloured rings by licensed ringers, birdwatcher and members of the public are not only most welcome, but necessary for this project to produce accurate data.

The RAS analyses generate two parameters: survival rates and re-encounter rates. The survival rates indicate the proportion of birds that survive and return to the site to breed each year, while the re-encounter rates provide a measure of the probability of a bird’s presence being detected should it have survived and returned; the higher the re-encounter rate, the more precise the survival estimate.