Colour ringed Avocets

Over the last 16 seasons an account of the Avocets at Leighton Moss has been kept and is available at Jim Shep's webpage.  The account gives excellent information on how many Avocets have attempted to breed at Leighton over the years and also the highly variable success they have enjoyed or, more often, endured.

Over the years a handful of colour ringed birds have appeared at the colony.  The first being a French bird (Red/White(O), Red/Lime).  From this record it would be very easy to assume the birds populating Leighton Moss were from the Southern populations spreading Northwards.

RWO-RL - The French Avocet

Last year two more colour ringed birds appeared (Red/Blue, Black/Black and White/Blue, Red/Green).  Interestingly these were ringed on the same day in 2015 at the same site on Teeside as chicks but not from the same brood even though the ring numbers are consecutive.  Further to this a third bird ringed on the same day, site etc appeared on the Ribble strongly suggesting many of the birds are populating from the East.

WB-RG - The second Cleveland bird

This year the French bird and Red/Blue, Black/Black have returned to breed.  Sadly the first breeding attempt of the French bird failed after 4 eggs were laid.  Additionally a metal ring only bird has had the ring number read.  This bird was ringed at Spurn in July 2013 as a chick adding further to evidence of birds populating Leighton are coming from the North-East.

RB-NN - The first Cleveland bird

In the last couple of days two 'new' colour ringed birds have been seen, firstly Lime/Blue, Lime/White which was ringed in May 2011 in Cleveland and a second bird appeared this morning (28th April) carrying a white engraved colour ring on the left tibia and green/metal on the right.  This appears to be a bird ringed as a chick in the Netherlands, exact details as yet unknown.

LB-LW - The third Cleveland bird

Once again these two records appear to add to the evidence of most of the population at Leighton are coming from the East and North-East confused by the first record being of a Southern bird.

Perhaps the origin of the birds being from the North-East is not quite so simple.  Does this reflect more on the ringing effort of Avocets than where they are coming from?  I took a look at where Avocets are ringed in the UK:

Of the 585 nestling Avocets ringed in the UK between 2010 and 2016 30% have been ringed in North Yorkshire and Durham however a tiny proportion of the breeding Avocet in the UK breed there.  Additionally most of the chicks raised in the North-East have been colour ringed so it is far more likely any from the North-East are marked whereas the probability of an East Anglian bird being marked is much lower.  In conclusion the movements suggest we are getting a lot of birds from the East but suggesting they are mostly from the North-East is ignoring the 90% of unmarked birds.

With the rapidly rising population of Avocet in the North-West it is not at all clear were the nestlings will disperse to.  Is Ireland a likely option or perhaps the Cumbrian coast spreading into Dumfries and Galloway?  With so much effort being put into understanding declining species it is easy to ignore the questions surrounding rapidly increasing species and as such perhaps an effort to colour mark chicks raised in the North-West should be made.

Selected histories of the 6 individually identified birds at Leighton Moss:

RWO-RL (The French bird, over 100 sightings in total):
20/06/2008 - Ringed as chick, Bas Boulais, France
Arrival/last sighting dates at Leighton Moss with next sighting for that year:
26/03/2012 - 17/04/2012 (France September)
28/03/2013 - 25/04/2013 (France July)
22/03/2014 - 29/04/2014 (Scunthorpe July, France Febuary 2015)
11/04/2015 - 18/04/2015 (20/04/2015 France!)
03/04/2016 - ?? (16/04/2016 Hesketh Out Marsh), no winter records
28/03/2017 - 23/04/2017 (November France)
05/04/2018 - 28/04/2018
If there is ever an example of why every sighting is valuable this bird is it.  In 2015 the last record at Leighton was 2 days before it appeared back in France.  Had we just had the first sighting of the season how long it stayed would be a complete mystery and whether it went directly back to France would be unknown.

RB-NN (EY98058):
Ringed 24/05/2015, Teesmouth
Sighted Alkborough, North Lincs 17/07/2015
05/04/2017 - 26/04/2017 - Leighton Moss
29/03/2018 - 26/04/2018 - Leighton Moss

WB-RG (EY98059):
Ringed 24/05/2015 - Teesmouth
Sighted Alkborough, North Lincs 19/07/2015
22/04/2017 - 26/04/2017 - Leighton Moss

LB-LW (EX15786):
Ringed 23/05/2011 - Teesmouth
Sighted Alkborough, North Lincs 08/08/2011, 13/07/2012, 30/08/2013
27/04/2018 - 28/04/2018 - Leighton Moss
Where has this bird been for the last 5 years?

EY21410 (No colour ring)
Ringed 03/07/2013 - Spurn Bird Observatory
27/04/2018 - Leighton Moss

White(EK) - Holland. More details to follow
28/04/2018 - Leighton Moss