Cheshire And Wirral Birding: Hills, Lowland and Coast (2 Viewers)

[deeestuary]

I know Rostherne Mere had around 220 breeding pairs of Cormorants last year, I don’t know how many they had thirty or forty years ago, but I suspect it would have been a lot less.

Any Cormorant observations welcome !!

The first recorded breeding of Cormorants in Cheshire was in 2004. So none 30 or 40 years ago!

This species is increasing dramatically in Cheshire/Merseyside both inland and on the sea as well documented in the C&W Bird Reports.
Also see comments about Cormorants on the Dee Estuary in my December Newsletter (including graph!) - http://www.deeestuary.co.uk/news1212.htm.
Given the coincidence of large increases both inland and on the sea I don't see any particular reason why breeding birds shouldn't move to the sea post-breeding. Also I remain far from convinced that the increases are anything to do with the Burbo Bank Windfarm, although it makes for a nice story if you are a wind farm enthusiast, which I'm not!

 

[Jane Turner]

I don't see any particular reason why breeding birds shouldn't move to the sea post-breeding

There aren't enough inland Cheshire breeders to account for the post breeding numbers Richard - that was the point.

I recall Cormorants up trees in the Grosvenor Estate in in 80s/90s... I'd always assumed that they were breeding. Obviously not.

 

[deeestuary]

There aren't enough inland Cheshire breeders to account for the post breeding numbers Richard - that was the point.

Obviously not but seems likely that many of those inland breeders do make their way to the coast. The BTO Migration Atlas suggests that most birds don't move very far from their breeding areas so probably the bulk of the birds we see are breeding in the UK - probably NW England and Midlands. I wonder what the proportion is of 'sinesis' and 'carbo' on the estuary?

 

[John Barber]

The first recorded breeding of Cormorants in Cheshire was in 2004. So none 30 or 40 years ago!

That information really surprises me. I'd assumed Cormorants had bred in Cheshire long before 2004.

Incidentally Richard, do you know how many breeding pairs there were in Cheshire as a whole last year ?

 

[Jane Turner]

Despite trying, I've never managed to clinch a sinensis here

 

[deeestuary]

That information really surprises me. I'd assumed Cormorants had bred in Cheshire long before 2004.

Incidentally Richard, do you know how many breeding pairs there were in Cheshire as a whole last year ?

Not seen any data for last year, but in 2011 the only breeding pairs other than that at Rostherne were 11 pairs at Trentabank Resevoir.

If, say, there were a total of 225 pairs breeding in Cheshire in 2012 and IF they all go to the Dee Estuary/Alt Estuary post breeding then that would account for 600 to 800 birds (including juvs), a substantial proportion of the numbers present. I suspect it's not as simple as that especially as they say the continental race ('sinensis' - which inland breeders mainly are) migrate/disperse much further than the UK coastal race 'carbo'.
Truth is we don't know where the breeding birds go post-breeding or where our coastal birds come from but it is true that this large increase in breeding birds has taken place at the same time as the increase on the estuaries - so quite possibly the same birds are involved.

 

[Mark Payne]

Not seen any data for last year, but in 2011 the only breeding pairs other than that at Rostherne were 11 pairs at Trentabank Resevoir.

If, say, there were a total of 225 pairs breeding in Cheshire in 2012 and IF they all go to the Dee Estuary/Alt Estuary post breeding then that would account for 600 to 800 birds (including juvs), a substantial proportion of the numbers present. I suspect it's not as simple as that especially as they say the continental race ('sinensis' - which inland breeders mainly are) migrate/disperse much further than the UK coastal race 'carbo'.
Truth is we don't know where the breeding birds go post-breeding or where our coastal birds come from but it is true that this large increase in breeding birds has taken place at the same time as the increase on the estuaries - so quite possibly the same birds are involved.

There is no way in the world the Cheshire breeding population could account for these number increases, the population isn't that high. These Cormorants are either coming from the Inland UK counties where a considerable increase has occurred, or they are even coming from the near continent when it freezes over. Take a look at the delta in BTO counts between numbers wintering / breeding UK http://blx1.bto.org/birdfacts/results/bob720.htm its clear to see number are swelled by populations other than our own, ok there will be non breeders knocking around the UK but they aren't going to account for a 20,000 difference.

 

[deeestuary]

There is no way in the world the Cheshire breeding population could account for these number increases, the population isn't that high.

I've already pointed out that "probably the bulk of the birds we see on the Dee Estuary are breeding in the UK - probably NW England and Midlands" i.e. not just Cheshire. But there has been a huge rise in breeding birds in Cheshire - from zero to around 220 pairs in just eight years so it is certainly at least possible that this rise has made a significant contribution to the rise in numbers on the local estuaries.
But have a look at the figures again - in 2003 (i.e. when NO birds bred in Cheshire) the max Dee Estuary BTO WeBS count was 692. The highest BTO WeBS count over the past couple of years was 1399 in the winter of 2010/11 (numbers dropped a bit last winter). The increase is 707. If each pair produce two young then the total post breeding population from 220 pairs would be 880 individuals, well over the 707 increase!! So your statement above is patently not true - sorry.

All I'm pointing out is that the breeding population had increased dramatically in Cheshire at the same time as the over-wintering population has increased, so the two are possibly linked, and the increase in breeding birds COULD account for the increase on the estuary. In reality it may well be that the Cheshire breeding birds disperse quite widely and that the over-wintering birds come from a fairly wide area - obviously the 692 birds in 2003 were NOT breeding in Cheshire for a start! Presumably breeding numbers elsewhere are also increasing and these will also be contributing to the increase in wintering numbers.

 

[Jane Turner]

There is no way in the world the Cheshire breeding population could account for these number increases, the population isn't that high. These Cormorants are either coming from the Inland UK counties where a considerable increase has occurred, or they are even coming from the near continent when it freezes over. Take a look at the delta in BTO counts between numbers wintering / breeding UK http://blx1.bto.org/birdfacts/results/bob720.htm its clear to see number are swelled by populations other than our own, ok there will be non breeders knocking around the UK but they aren't going to account for a 20,000 difference.

It looks like the latter, or at least the extra birds are coming some distance. The graph shows avg Cormorant count by half month. The biggest increases are in Nov-Feb, whilst if anything there are fewer birds in summer

 

[deeestuary]

It looks like the latter, or at least the extra birds are coming some distance. The graph shows avg Cormorant count by half month. The biggest increases are in Nov-Feb, whilst if anything there are fewer birds in summer

Yes, interesting graph. WeBS Report 2010/11 shows a UK max reached in September with numbers in July and August also high - which is what you would expect if the birds are mainly UK breeders. Of the top five sites max is in September in Loughs Neagh and Beg (1,192) and Morecambe Bay (1,047), and max was in November on the Ribble Estuary (928). Max on Dee Estuary was 1,399 in December and on the Alt Estuary was 1,459 in February. This seems to show that birds are moving around the Irish Sea so perhaps are not moving a great distance.
Just a couple more points which may be of interest - after 20 years of increase numbers nationally have been stable over the past 10 years (possibly due to culling) This is in contrast to the above sites - numbers in Northern Ireland have shown a small decrease whereas all those other Irish Sea sites mentioned above have shown a fairly substantial increase. Whether this increase in our NW Estuaries reflect increases in the local breeding population I don't know, but it seems a reasonable conclusion to make.

 

[Jane Turner]

Its dangerous to base too much on one year - what would be fascinating to see is a similar 40 year data set from Walney - to see it they also see a disproportionate increase in wintering birds or whether the increases here are a redistribution of the East Irish Sea population.

The only rings I've found have been from N.Welsh birds coastal birds...Puffin Island & Anglesey - but not enough to base anything much on - but intriguing all the same.

 

[deeestuary]

Its dangerous to base too much on one year - what would be fascinating to see is a similar 40 year data set from Walney - to see it they also see a disproportionate increase in wintering birds or whether the increases here are a redistribution of the East Irish Sea population.

The only rings I've found have been from N.Welsh birds coastal birds...Puffin Island & Anglesey - but not enough to base anything much on - but intriguing all the same.

Sorry - I should have made it clear that 2010/11 was just an example, other winters over the past 10 years show a very similar pattern with Morecambe Bay usually peaking in September and the Ribble, Dee and Alt peaking in different months between Nov and Feb. Nationally also there is usually a peak in September with the occasional peak a month later in October. There is an interesting comment in the 2009/10 WeBS Report that the breeding population in the UK actually dropped 7% between 2000 and 2010. Certainly a contrast to those in Cheshire!

 

[Jane Turner]

While you have the WeBR reports to hand - what is the story wrt Great Crested Grebes? Its hard to explain their local post 2004 population explosion with breeding changes

 

[deeestuary]

While you have the WeBR reports to hand - what is the story wrt Great Crested Grebes? Its hard to explain their local post 2004 population explosion with breeding changes

Have a look at http://www.deeestuary.co.uk/news1210.htm. Although there have been several higher counts since that was written the main conclusion still stands - that the birds are probably not local breeders but come from Northern Ireland and/or Scandinavia where large numbers breed. Speaking for myself the reason why there have been larger counts over the past couple of years is that I've become better at counting them - knowing where the main concentration of birds are, the best height of tide to count them and, most importantly, the best weather conditions. You, Jane, still hold the record for the highest count of 1,195!! I'm not far behind with 976 last November.
Nationally there has been a small decline in over-wintering birds over the past few years - other than that WeBS is not particularly informative especially as no North Wirral counts were submitted to WeBS prior to 2006.

 

[Jane Turner]

I've been looking hard since 2000, and you can put some uplift in numbers down to having an elevated view and better optics than in 1the 70s-90s... but the real increase started in 2005.

http://www.birdforum.net/attachment.php?attachmentid=432222&d=1363080828

 

[deeestuary]

"you put some uplift in numbers down to having an elevated view and better optics than in 1the 70s-90s"

I don't remember saying that but if your graph shows the big increase in numbers didn't start until 2005 I have no problem with that. As I didn't start counting until late 2006 I can't comment on how many birds were out there prior to then.

An elevated view certainly helps, though!

 

[Cheshire Birder]

Today - Green-winged Teal and 3+ Avocets at Burton Mere Wetlands; Great White Egret at Hale; 11 Waxwings at Bebington plus 21 at Northwich and 20 at Bromborough; White Wagtail, 30 Pied Wagtails, 3 Stonechats and 4 Jack Snipe at Leasowe;

Yesterday - Mediterranean Gull at Meols;

CB

 

[Cheshire Birder]

Today - Great White Egret at Hale; Long-tailed Duck at Woolston Eyes; Mediterranean Gull, 5+ Avocets and Hen Harrier at Burton Mere Wetlands; 9 Scaup, 2 Eider, 10 Little Gulls and 2 Stonechats at Leasowe; 2 Lesser Spotted Woodpeckers at Moore NR; 4 Little Egrets, 67 Pink-footed Geese and 2+ Bramblings at Frodsham; Short-eared Owl at Burton;

CB

 

[Jane Turner]

Was surprised to see/mostly hear a Lapland Bunting at lunchtime - over the point at Red Rocks, heading down the estuary.

 

[Cheshire Birder]

Today - Great White Egret at Hale; 6 Waxwings at Wallasey; Wheatear, 3 Stonechats and Greenshank at Leasowe; Spotted Redshank at Burton; White Wagtail and Green Sandpiper at Frodsham; Scaup at Moore NR;

CB