Dee Estuary Birding

You would be forgiven to think that until recently it was still winter with the cold, windy and rainy weather we had, and the presence of several thousand Red Knot, mainly in grey plumage, feeding off the shore at Leasowe.
…..but hold on a minute, this is June!  What is going on?

Red Knot (Calidris canutus islandica) are a very common winter sight along the Wirral shoreline at many sites (Thurstaston, West Kirby, Hilbre, Hoylake, Meols, Leasowe) where they are present in internationally important numbers. They also form part of the wader murmuration you may see on the incoming tide or when the waders are under attack by birds of prey such as Peregrines.

In winter Red Knot have a grey plumage but as the adults head into late March/early April their breast feathers start to moult into a lovely orange-red breeding plumage, hence the name Red Knot. However, Knot born in the previous year (at this time called 2CYs as they are in their 2nd calendar year) retain their grey plumage. Before the adults turn red, 2CYs can be identified by their patterned juvenile wing coverts which wear and fade to buff due to being poor quality feathers quickly grown in the Arctic. By May, adults and the 2CY Knot can be easily told apart as adults have some amount of red plumage while the 2CYs are still grey.

OK so we know the grey birds we are seeing at Leasowe are 2CYs but why are they here in June? Hardly any 2CY Knot go north to the Canadian Arctic via Iceland to breed. This is also the case for a small proportion of 3CYs (Knot in their 3rd calendar year) as well. These Knot stay at a few summering sites in the UK, principally the Wash and Liverpool Bay, and a few sites in the Dutch and German Wadden Sea. Survival of the Knot at these sites is vital to the long-term survival of the species, as the 2CYs are the future breeding population.

So, the Knot at Leasowe are mainly young birds, but why are they at Leasowe? Part of the reason is that 2023 was a very good breeding year so there are many 2CYs about in 2024. OK, but 2019 was also an excellent breeding year for Knot and during the early summer of 2020 there weren’t any on the Wirral coast. In the summer of 2020, the Ribble estuary had over 20,000 Knot summering there. That year survey reports for cockle and mussel beds undertaken by the North Western Inshore Fisheries and Conservation Authority show there were large numbers of cockles in the Ribble estuary but none at Leasowe. In 2024 there are good numbers of cockles at Leasowe as well as the Ribble.

Ok we are seeing these Knot in June because as 2CYs they did not go north to breed and have a good supply of food, but if you visit Leasowe at high tide you won’t see any. Why? The Knot are feeding there for about three hours either side of low tide but come the high tide they have been flying off to roost at Seaforth Nature Reserve in Liverpool Docks. We know this as some of these Knot carry colour marks which can be read in the field and we have observed the movement between feeding around low tide at Leasowe and roosting around high tide at Seaforth.

You can learn a lot about Knot behaviour using colour marking. It is a valuable tool to understand survival, behaviour and migratory pathways. This year coded orange flags were put on 668 young Knot at sites in mid-Wales (Dyfi estuary), north Wales (Bangor, Llanfairfechen), in Liverpool Bay (Hoylake, Ainsdale) and in Scotland (near Inverness). As of 23rd June, 201 of these orange-flagged Knot have been seen at Leasowe and at Seaforth since mid-May. Interestingly only one is from the 120 colour marked in Scotland. Furthermore, young Knot colour marked on the Wash and in the Netherlands this past year have not so far been observed this summer in Liverpool Bay. Where else have orange-flagged 2CYs been observed? Some of them, including a greater percentage marked in Scotland, have been observed summering in the Dutch and German Wadden Sea along with Wash and Dutch colour marked birds.

It’s nice to see these waders on the Wirral in summer. How long will they be here? It is likely that many of the Knot will stay here for a while. Some of them have already started to replace their worn juvenile primary wing feathers as well as their body feathers and so in the next few months we don’t expect them to fly great distances. However, the only other time that we have colour-marked lots of 2CY Knot, in May 2021, we found that after spending the summer on the Ribble, most left Liverpool Bay in late autumn. So, it will be important to discover whether this current Knot flock also disperse in the autumn. We hope that when the adults start arriving back from the breeding grounds in the Canadian Arctic in late July, still in their red breeding plumage, some will join these 2CYs and there will continue to be an impressive sight of waders at Leasowe.

Rose Maciewicz and Peter Knight