Dee Estuary Birding

"Movements and records of this species continue to be bewildering in terms of trying to establish a regular pattern." Cheshire Bird Report 1976.

"The erratic occurrence of the Little Gull makes it difficult to judge its true status, abundance and any rate of change" and "The transient and ephemeral nature of the Little Gull makes it difficult to judge its conservation status."  The Birds of Wales (2021).

Little Gull - an intriguing species and I picked out the two quotes above, 45 years apart, to demonstrate that there is an awful lot we don't know about them. They spend the winter mostly out of sight from land so we have little idea exactly where they are or how many, and they breed around remote lakes in Scandinavia and east to Siberia where they are difficult to monitor. As you will read below, when they are on migration they are much easier to see but even then they are subject to abrupt changes of routes and numbers. We are  lucky here on the edge of Liverpool Bay where for the past forty years they are routinely seen on spring migration. Although numbers have dropped from what they were in the first decade of this century Liverpool Bay remains the best place in the UK to see Little Gulls on spring passage and there were 86 off North Wirral this last spring on the early date of March 5th 2024, which is the highest number we've seen here since 2016.

History of Little Gulls

In the Birds of Cheshire (Ref 1) T. Hedley Bell says that they were known as winter rarities going back to the 19th century, and far less than annual, but by the time he wrote his Supplement (Ref 2), in 1965, they were more often seen in summer and autumn although still mostly just single birds. But there was a hint of an increase in numbers with a report of the largest party so far recorded in Cheshire/Wirral with nine off New Brighton in September 1965.

"The status of the Little Gull Larus minutus in Liverpool Bay has changed dramatically since 1965" (Ref 3). So wrote Ray Eades, who some of you will remember, in 1982. From 1963 to 1976 Ray counted Little Gulls almost on a daily basis whilst working as a Pilot and I can do no better than to illustrate the dramatic change by reproducing the table in the article he wrote for the 1977-1981 Seabird Report.

From none at all in 1964 and 1965 numbers increased just eleven years later to 661 in 1976. Two things I noted in the article was that, (1 ) all but 5% of records were in summer and autumn, and (2) nearly all the Little Gulls were in the Crosby/Formby Channel (i.e. in the Channel between Formby Point and Seaforth), with very few in the area between the Bar Lightship and Point Lynas on the north-east coast of Anglesey.

J.D. Craggs writes in the Hilbre book (Ref 4) summarising records gathered by the Hilbre bird Observatory between 1957 and 1977: Records have increased in frequency from 1970 before which we had only 2. Numbers are extremely variable and the peak was reached in December 1975 when 135 were seen on the 7th and 128 on the 21st - no doubt the same flock. At that time numbers in spring were very low, something which was soon about to change.

It wasn't just Liverpool Bay where numbers of Little Gulls increased dramatically, similar increases were being seen right across the country as detailed by Hutchinson and Neath in their British Birds article (Ref 5). I reproduce their bar chart for Lancashire, Cheshire and Flintshire which is a summary of land based records going all the way back to 1934, and it shows a similar pattern to Ray Eades' ship based records.

What caused this massive increase in the late 1960s and early 1970s and beyond isn't clear. There is evidence for a western expansion of the breeding range into Finland with BWP (Ref 6) stating that they had increased from 200 pairs in 1958 to over 1,000 pairs by 1980 - although the numbers all seem a bit vague. Since then expansion has continued with a north western movement of their breeding range with less breeding in the countries bordering the south-east shore of the Baltic and more in Sweden and Norway, as shown when comparing the first European Breeding Bird Atlas (1980s) with the second (2013-17) (Ref 7). Finland, and further east into Russia, still remains the most important breeding areas. With the current European population estimated at 23,700-45,200 pairs, which equates to 47,400-90,500 mature individuals (BirdLife International 2015 Ref 8), that estimate of 'over 1,000 pairs' in Finland is surely a big underestimation, even if it's technically true. But all this doesn't explain the sudden increase in the UK in just 10 years, so it seems likely that there must have been changes in migration routes and wintering areas to go along with the range expansion, probably they found good sources of food in the Irish and North seas, and further south.

Liverpool Bay - A big increase in spring

Whilst the majority of Little Gull records for the country in the 1970s were, and still are, in late summer and autumn - that was about to change in Liverpool Bay. There were signs of increasing numbers in spring with 30 off Red Rocks on March 27th 1977, 53 off Hilbre on March 9th 1979 and 205 off Meols on April 4th 1982. On the Sefton coast the Little Gulls were being monitored by Philip H. Smith with frequent visits between January 1975 and December 1984. Using these, and earlier observations, Smith published a table in Ref 9 that showed between the years of 1969 and 1974 1.1% of the Little Gulls recorded were present in April and 58.7% in August/September. In contrast, between 1975 and 1984 51.7% were seen in April and 25.4% in August/September. A remarkable turnaround.

For the next 30 years Liverpool Bay became the Little Gull capital of Britain! Here's a couple of bar charts to illustrate numbers.

The first counts of over 100 off Hilbre came in 1975 when a flock of up to 135 was seen several times over November and December that year. Most peak counts prior to 1980 were in summer or autumn, but after 1980 they were all in March or April.

At Seaforth/Formby all peak counts between 1980 to 2024 came in April. Up until the last few years all these high counts were made at Seaforth or the adjacent Crosby Marine Lake, but with the recent low numbers there have been some higher counts made at Formby, including 65 in 2023.

The bar chart above shows the weekly distribution for Little Gulls off the Dee Estuary and North Wirral for the past 10 years (2015 to 2024). You can clearly see how the large majority of records are between the first week of March and the third week of April, whereas the return passage, in September and early October, is virtually non-existent in comparison.

The usual pattern of spring arrival is that Little Gulls are first seen off Hilbre and North Wirral in late February or during March. Here they are often recorded dip feeding and occasionally roosting on sand banks with West Hoyle Bank a favourite spot.  Most years they will only be recorded on a few days with, typically, numbers varying from around 10 up to 60 or more. They appear to use Liverpool Bay as a staging post in March and they are also often seen off Formby at this time, with probably larger numbers further out. Sadly, the gathering in April and early May of hundreds of Little Gulls at Crosby Marine Lake and Seaforth, where they fed on non-biting midges (Chironomid), no longer takes place with the last big count being on May 2nd 2012 with 183. The high count of 172 in April 2015, was off Formby.

There have been two very big counts at Hilbre this century - one in 2006 and the other in 2011. The bar chart above, for 2006, shows nicely the transient nature of this species as recorded from Hilbre with just two days of three-figure counts, compared to Crosby Marine Lake and Seaforth where they were present in good numbers throughout April.

Chris Felton was the lucky observer on Hilbre on March 20th 2006 and he wrote an article about his experience which was published in both the Hilbre and Cheshire & Wirral Bird Reports for 2006. I loved his description of the Little Gull flocks and here is a short extract (there was a brisk easterly wind blowing which the birds were flying into):

"I caught sight of a flock of Little Gulls Larus minutus, making it's way towards me from across the mouth of the Dee. Eventually, 111 came along, strung out low over the water, rising and dipping, butterfly-like, as they passed, the black underwings clearly noticeable. As Some birds landed briefly on the water, those behind leap-frogged over them causing them to take flight and hastily catch up."

In all Chris saw around eight distinct groups mostly of around 60 birds, and with clear gaps in between each flock. The total was 628, and, at the time, the highest ever March count for Liverpool Bay.

An even higher count came on March 31st 2011, as described in the Hilbre Bird Observatory Blog for that day:

"After overnight rain a west south westerly blew up to force 6/7 and then gale force 8 by 08:00hrs. With obviously not much action to be expected on the migration front, sea watching was the main attraction this morning. Right from the off flocks of Little Gulls were seen moving west in a narrow band in the medium distance (above, the sort of view one might see through binoculars!), in large groups at first and then thinning out later in the morning. The end of the session total came to 651 birds, a record count for Hilbre."

Where do they spend the winter?

We don't know for sure where these Little Gulls spend the winter but both Smith, writing in 1987, (Ref 9) and Messenger, writing in 1993 (Ref 10), concluded that it was very likely that the large majority of the Little Gulls we see in Liverpool Bay in spring had spent the winter in the Irish Sea. An examination of recent records up to the present time strongly suggests they still do.

I've shown the map, above, which was published in Ref 10 in 1993 because the exact same map could be drawn today. The shaded areas show 'The only area with regular counts over 25' - and that applies to the whole of the Irish Sea, not just the portion shown. It took Messenger a lot of work to find and collate all the data but these days we have BirdGuides and I was able to look at all records from around the Irish Sea for December and January since the turn of the century and, for those two months, I found 14 counts of over 25 in the area just south of Dublin and along the Wicklow coastline (max 155 in 2013), and 21 counts of over 25 between the south coast of Morecambe Bay to Seaforth (max 195 in 2005). Messenger said "Little Gulls usually begin to arrive on these coasts immediately the winds exceed force 3 and, as they increase in severity, so more gulls arrive", the fact that the flocks appear so soon after the onset of fresh on-shore winds must mean the birds are not far from the coastline. There were no flocks of over 25 elsewhere in the Irish Sea over that period.

As well as the BirdGuides data, aerial surveys were carried out over Liverpool Bay during the winters of 2004/05, 2005/06 and 2010/11 which specifically looked for Little Gulls. They came up with a figure of 333 based on the mean peak over those three winters (Ref 11). Most of the Little Gulls were around 12 miles out off Blackpool, and the figure of 333 was thought to be an underestimate.

The data indicates that the two areas (the east coast of Ireland off Wicklow, and the Lancashire coast) are discrete with little interchange as Little Gulls are virtually unknown on the Isle of Man in winter, with just the occasional single bird on Anglesey and elsewhere along the Welsh coastline. It's strange that westerly gales don't result in flocks of Little Gulls from the east coast of Ireland ending up on the Welsh coast, but it doesn't appear to be the case.

The Spring Passage

The several hundred Little Gulls which winter in the Irish Sea may well account for most of the birds we see in spring in Liverpool Bay but that doesn't mean we don't also get a movement of birds which have wintered further south. However, Smith (Ref 9) points out that there is no evidence for such a northward movement with this species virtually unknown in the Scilly Isles and just the odd single birds off the west coasts of Cornwall and Pembrokeshire - and that is the case now as it was in 1987. But here is a puzzle - in April 2023 there was a big movement of Little Gulls up the Severn Estuary including 217 past Severnside on the 20th, with many double-figure counts elsewhere. Yet not a single Little Gull was recorded off the west coast of Cornwall, Pembrokeshire or the Scilly Isles in April 2023! So if Little Gulls are getting into the Severn Estuary unobserved they could certainly also arrive in Liverpool Bay out of sight. Although the passage up the Severn Estuary in 2023 was exceptional flocks in double figures are not unusual there in April most years, including 26 which 'spiralled north-east' from Severn Beach on April 20th 2022 and 51 which were over South Lake at Slimbridge WWT on April 8th 2018 which flew north-east.

From Liverpool Bay the Little Gulls fly eastwards across the country during April. Messenger (Ref 10) details observations from tha Alt Estuary and Seaforth of parties up to 50 strong spiralling high and disappearing as they flew east. Most must fly all the way to the east coast without stopping but there are regular reports of small numbers dropping down onto reservoirs and lakes en route. Some birds seem to take a more southerly route as they did in 2023 when an unprecedented 67 were counted at Woolston Eyes  on April 19th, breaking the previous record count of just nine; It was probably no coincidence that several parties of Little Gulls were seen in Yorkshire the following day including 60 flying east past York and at least 30 at Fairburn Ings, indicating a big overnight passage.

Thanks to ringing the evidence that these Little Gulls end up in Finland and nearby countries is strong. A total of 16 Little Gulls ringed at Seaforth have been found elsewhere including several in Finland and one well into Russia, in the Arkhangelsk Oblast 2,759Km from Seaforth (Refs 12 and 13).

Huge numbers at Hornsea Mere and the East Yorkshire Coast

Although on the other side of the country from the Dee Estuary, I can't finish this article without mentioning Hornsea Mere and the adjacent Yorkshire coast as it's a classic example of very big numbers of Little Gulls appearing in an area where they were virtually unknown before. I start with an article in British Birds 'Little Gulls at sea off Yorkshire in autumn 2003' by Clive Hartley (Ref 14). During a ship-based survey on 11th-12th September 2003 off the Yorkshire coast, between Flamborough Head and Spurn Point, he came across large numbers of Little Gulls and Kittiwakes feeding about 12 miles out from the coast - the number of Little Gulls far surpassed all previous records. They were seen "feeding... often in a frenzy of activity with other seabird species" and he noted "these flocks took the form of dense clusters, containing up to 120 Little Gulls". The number of Little Gulls counted during that survey was estimated to be at least 9,500, this number was confirmed on the evening of September 12th 2003 when an unprecedented 10,000+ were recorded offshore from Spurn Bird Observatory.

Hornsea Mere is just one mile from the East Yorkshire coast, almost exactly halfway between Flamborough Head and Spurn Point where these big feeding flocks of Little Gulls were being seen. The first mention of large numbers of Little Gulls on the mere I can find was by Hartley when he wrote that 3,000 were there in September 1997. Numbers continued to increase with 7,000 in 2004 and 16,000 in 2006, both in September, then a truly massive 21,500 in August 2007 - what a spectacular sight that must hve been! Numbers have never been quite as high since but there have still been some big counts including 8,200 in August 2021. The birds use Hornsea Mere as a roost site and fly in in the evening, presumably after feeding off-shore during the day.

References and sources of information:

I have used records from Cheshire & Wirral Bird Reports, Lancashire Bird Reports, Wetland Bird survey (BTO) and BirdGuides throughout the article - for which many thanks to all.

Here is the list of References mentioned in the text:

1. T. Hedley Bell, The Birds of Cheshire, 1962.

2. T. Hedley Bell, Supplement to The Birds of Cheshire, 1967.

3. R.A. Eades, Notes on the distribution and feeding of Little Gulls at sea in Liverpool Bay. Seabird Rep. 6: 115-121, 1982.

4. J.D. Craggs (Editor), Hilbre - the Cheshire Island, 1982.

5. C.D. Hutchison and Brian Neath, Little Gulls in Britian and Ireland, British Birds 71, December 1978.

6. Birds of the Western Palearctic (BWP), App edition, 2023 (NatureGuides Ltd).

7. The European Breeding Bird Atlas 2, https://ebba2.info/ (last updated 2024).

8. Birds in the European Union: a status assessment (BirdLife International, 2004).

9. Philip H. Smith, The changing status of Little Gulls Larus minitus in north Merseyside, England, SEABIRD 10, 1987.

10. Doug Messenger, Spring passage of Little Gulls across Northern England, British Birds 86, September 1993.

11. J. Lawson et al., An assessment of the numbers and distributions of wintering waterbirds and seabirds in Liverpool Bay area of search, JNCC, 2016.

12. Robinson, R.A., Leech, D.I. & Clark, J.A. (2023) The Online Demography Report: Bird ringing and nest recording in Britain & Ireland in 2022. BTO, Thetford (http://www.bto.org/ringing-report, created on 21-September-2023).

13. The Eurasian African Bird Migration Atlas, https://migrationatlas.org/ , 2022.

14. Clive Hartley, Little Gulls at sea off Yorkshire in autumn 2003, British birds 97, September 2004.

Richard Smith