Ian, one of our Group members, recently saw a marsh harrier at Elmley with wing tags. Many bird species are ringed, and with marsh harriers there has been an ongoing project on the Isle of Sheppey to place coloured and numbered tags on individuals in the nest so that their progress can be tracked. As you can see from the photograph, the individual that Ian saw had a orange tag ’63’ on it. To read more about it click here.
Having sent the information off to the Swale Wader Group who conduct the work we got the following information.
This bird was ringed (as a male) and tagged in the nest at Elmley on 18th July 2013. It was one of a brood of five. The bird was seen around the Reserve on both 4th and 10th August in the same year, but by 24th October 2013 he had moved near to Strumpshaw Fen some 143 km from Elmley.
In January 2014 ’63’ was seen in Loddon, Norfolk, with another tagged marsh harrier.
The next sighting is Ian’s, on 3rd March 2016, and from the photograph you can see that it is most probably a female – which in itself is valuable information for the project. Hopefully she is back to nest at Elmley herself.
Interestingly, you may recall that some of us also saw a wing tagged marsh harrier in 2012 at Grove Ferry. This had been tagged as a fledgling at Stodmarsh in 2010. By the time we saw it again, it had developed into a handsome male and although it had not been seen in the intervening two years it was back in the place it was bred.
It’s interesting that they appear to go away from the breeding ground for a couple of years then return to the place where they were born. The typical age that they start to breed is 3 years, so it may be that they are coming back to set up their own territories.
Conservation status of marsh harrier in the UK is Amber, with around 400 pairs believed to be present in the summer. The typical proportion of juveniles surviving to the age of 3 is 0.151. The proportion of adults that survive each year is 0.740.
So, given this information it shows how lucky we are in Kent to see marsh harrier so regularly, their population increases with wintering birds roosting in large numbers in reed beds. The numbers then reduce as they disperse in the spring to go back to their breeding areas.
Information such as Ian’s is vital to the ongoing research of this beautiful species.
Reference: Balmer & Peach 1997 Review of natural avian mortality rates BTO, Thetford