West Sussex Stilts and Turtle Doves (25-26 May)

Monday 26 May.  I started on the Adur at low tide on the off-chance I might get a confirmed reading of yesterday's presumed Buckinghamshire Herring Gull.  It was not amongst the few gulls there although another North Thames Herring Gull was, along with 5 Ringed Plover.  I met John King and we drove to Earnley.  We had not been to Medmerry from this side but had not picked the best day to go - so much for the pre-weekend forecast.  It was an impressive area and we saw the pair of Black-winged Stilts, 5 pairs of Avocets (two sitting, the others 3 with 3, 1 and 1+ chicks), a pair of Little Ringed Plovers with 2 chicks, single Greenshank, Sanderling and Dunlin and 2 Curlew.  Despite continual light rain the walk there and back produced 2 Cuckoos, 4 Yellowhammers and a Corn Bunting.  We called in at Church Norton to take advantage of a brief improvement in the weather and a falling tide, seeing 36 Sanderling, 15 Dunlin, a summer-plumaged Knot, 40+ Ringed Plovers, a Bar-tailed Godwit and two each of Little, Common and Sandwich Terns.  The rain restarted as 2 Red-legged Partridges scuttled across the churchyard.  There were 6 Avocets and 9 Black-tailed Godwits on Sidlesham Ferry and 300 Swifts and 25 House Martins over Ivy lake.  An enjoyable day despite the weather.

Black-winged Stilt on nest at Medmerry

the eggs were left unattended (but guarded by RSPB volunteers) for several minutes between shift changes.  it seemed a long time in the cold wet weather.

the nest seemed to have involved no building or scraping at all and was rather too close to the waters edge for comfort, at least on a wet day

those legs were not designed for sitting on

it was surprisingly well camouflaged when sitting, although the dull weather doubtless helped

 

North Thames Herring Gull F9BT on the Adur.  Now in its third calendar year, I had seen it on the beach at Widewater in February 2013

Sunday 25 May.  With a stronger wind than forecast I seawatched at Widewater from 06:30-07:30 seeing 57 Gannets, 66 Common Scoter and 20 Sandwich Terns.  There was no enough visibly passing to keep my interest but it looked like another day that I would have done better going to Seaford.   Back on plan I headed for the Knepp Estate.  In much nicer weather than my previous visit I heard then saw 2 superb Turtle Doves, 2 Cuckoos and a Garden Warbler.  I also saw 2 male Mandarins, 2 Red Kites, Lapwing, 3 Stock Doves, 2 Great Spotted Woodpeckers at a nest hole, 9  Mistle Thrushes, 2 Jays, Treecreeper and 4 Bullfinches.  I also heard Nightingale and Yellowhammer.  Taking advantage of the nice weather Megan and I walked up Southwick Hill to Thundersbarrow where 15 Swifts and a House Martin were flying low over the fields.  a later afternoon low-tide visit to the Adur produced two colour-ringed Herring Gulls, North Thames TM9T that I'd seen there on 16 May (and in March and July 2013 following sightings in Essex, Kent and Pas-de-Calais) and what appeared to be 0956, likely from Gerrards Cross Landfill in Buckinghamshire.

Fallow Deer on the Knepp Estate

Turtle Dove on the Knepp Estate

When I started birding I rather took Turtle Doves for granted.  Without trying I averaged about 50 per year from the early 1970s to the mid 1980s (including over 200 in 1981) but numbers have been falling increasingly rapidly ever since.

I saw just 6 Turtle Doves during 2010-13.  Maltese hunters are probably not entirely responsible for the decline but they can not be helping.  Where are the EU when you need them?  Full marks to Chris Packham for highlighting their plight, the most worthwhile thing he's done so far IMHO!

colour-ringed Herring Gull considered to be 0956, I couldn't be certain of the 9 and while moving closer the bird stepped into a hollow obscuring the first two digits.  It then flew off as a bait-digger approached.  Previously on the Adur I had seen two birds ringed at Gerrards Cross Landfill (Bucks), 0977 in July and November 2012 and 0595  in November 2006.  It is a good bet this is a third.

Saturday 24 May.  A weekend day in late May, potentially what could be better in Sussex, but after a seawatch from Shoreham Fort which produced a Fulmar, 2 Gannets and 11 Sandwich Terns I returned home and spent much of the rest of the day scanning old holiday pics.

Monday 19-Friday 23 May.  Cycling to and from work I saw the Power station Peregrines twice, once the male was on the 'ring' directly above the female and he looked tiny.  One or two Ringed Plover were seen most days with possibly 4 birds involved, a Stock Dove visited our garden regularly with up to 5 Swifts seen over our road each evening.  Less usual from the bike were 3 Gannets off Brighton seafront and a Sparrowhawk over our house, both on 23rd.

Stock Dove on our bird table

Seaford seawatch & South Downs monitoring (17-18 May)

Sunday 18 May.  The forecast of a south-easterly, albeit a light one, made me feel that a final spring seawatch might be worthwhile.  I arrived at 05:40, a minute before John King, and an hour later was wishing I'd stayed in bed.  That all changed when a superb pair of Garganey flew east just off the beach at 06:47.  The morning got even better when two pale Pomarine Skuas flew east close inshore at 07:13 (they were clearly motoring as they were seen passing Birling 9 minutes later).  John King and I ended up staying for 7 hours.  Being in the company of Bob Self for much of it helped pass the time as passage was fairly slow but I ended up noting Red-throated Diver 1E, Gannet 22E, Shelduck 1E, Garganey 1 pair E,  Eider 1 imm male on sea, Common Scoter 415E, Sanderling 15E, Knot 1E (winter plumage), Whimbrel 1E, Pomarine Skua 10E (all pale, 2@07:13, 09:07, 09;10, 10:14, 11:11, 3@11:37 & 12:12), Arctic Skua 4E (all pale, after 11:00), skua sp. 1 on sea (landed at 12:00 before it could be unidentified but Pom suspected), Black-headed Gull 35E, Sandwich Tern 85E:3W, Common Tern 14E, Little Tern 3E, Guillemot 1E, auk sp. 3E, Swallow 1 in and Raven 1.  Similar totals for many species to the Beachy blog although only the first Poms were seen there.  The next two were a bit further out but the 10:14 bird was close, although put down on the sea a couple of times off Seaford and so did not appear to be in a hurry.  The others would have been after observations stopped at Beachy.  Less good for us was not seeing any Black Terns (Birling had 8).

Saturday 17 May.  My South Downs monitoring square near the Burgh was due its first visit.  It included an area where I had seen Turtle Dove last year which seemed a good reason to choose it.  No luck on this occasion but I did see 8 Grey Partridges, Red Kite, Cuckoo, 4 Mistle Thrushes, Marsh Tit (!), Yellowhammer and Corn Bunting. Less pleasant was a Magpie in a Larsen trap, not illegal but disappointing in an area that appears to do a lot for wildlife although seeing comments on Martin Casemore's excellent Ploddingbirder blog (http://ploddingbirder.blogspot.co.uk/2014/05/pas-de-calais.html) perhaps puts my squeamishness in context.  I'm also told authoritatively that Larsen traps are the least worst method of control so maybe I would not have seen Yellowhammer or Corn Bunting if they were not being used?

I went on to Littlehampton West Beach but had misjudged the tide which was higher than anticipated and there was no sign of the Kumlien's Gull.  Twelve Sanderling were on the remaining exposed sand and I heard a Cetti's Warbler behind the Golf Course but the only possible sign of migrants were 3 Swallows.  A walk around Lancing Ring and Steepdown with Megan produced more Yellowhammers and Corn Buntings than I had managed around the Burgh.

approachable Red Kite near the Burgh

Cuckoo near the Burgh

Corn Bunting

Magpie in a Larsen trap near the Burgh.  Their use is not illegal provided strict guidelines are followed and Magpies do take many nestlings but watching this bird almost constantly jumping around trying to escape made me feel that there must be a better way to control them but I'm told this is the least worst way (see above).

Friday 16 May.  The warmest day of the year so far seemed a good evening for a Woodcock survey at Lavington.  On the way I called in at the Adur seeing North Thames Herring Gull TM9T and two Ringed Plovers, then Greatham seeing a pair of Mandarin but not a distantly calling Cuckoo.  I probably saw 3 Woodcock at Lavington in what I felt was a disappointing session. Three Nightjars were calling, two quite close, but I failed to see them. Three distant Tawny Owls were also calling.

this gull caught my eye but so many immatures are looking very faded now

North Thames Herring Gull TM9T on the Adur.  I had seen it in March & July 2013.  It had been ringed Pitsea Landfill (Essex) as 1CY on 05/09/10, seen Dungeness on 17/11/10, Crayford Creek, N Kent on 21/01/11, Boulogne-sur-Mer Harbour, Pas-de-Calais on 18/11/12 and Holland Haven (Essex) on 17/12/12

Monday-Friday 12-16 May.  A Peregrine was on the Power station chimney most days with a Rock Pipit by the lock-gates twice and 2 Wheatears on Southwick Beach on 14th.  At dusk on 12th there were 19 Swifts over our road and we had a pair of Stock Dovves in the garden on 15th.

Normal service resumed (10-11 May)

Sunday 11 May.  With no sign of the strong winds abating, and coming from a direction not conducive to seawatching I decided to have a morning at inland sites trying and see a few summer visitors I'd not yet caught up with before watching Louis Hamilton just win the Spanish Grand Prix.  John King joined me and we visited the Knepp Estate (Cuckoo, Garden Warbler, Bullfinch & Yellowhammer), Greatham (Swifts, Sedge Warbler) and Pulborough RSPB (Spoonbill, Egyptian Geese, 15 Ringed Plovers, Nightingale and a Nuthatch on the feeders).  

Nightingale at Pulborough

Saturday 10 May.  Two hours seawatching from 06:55, initially from the end of Shoreham Harbour (very exposed) then Widewater (hut 32 providing some shelter), was disappointing.  I'd hoped that the strong WSW wind might have brought something in but poor visibility may not have helped.  Most birds seen were heading west into the wind: 21 Gannets, 6 Fulmar, 5 Common Scoter and 3 Whimbrel.  Three Swallows came in while offshore a female Eider was being harassed by gulls and a handful of Sandwich Terns cruised past. Nothing of note was seen on the Adur either then or later, at low tide, with Megan.

Tuesday 6 to Friday 9 May.  I saw the first Swifts over our road with 6 on 6th and 15th on 7th but lower numbers subsequently as the wind picked up and a Peregrine was on the Power Station chimney each day.

More on 5 May Poms

Following record numbers of Pomarine Skuas off Seaford and Birling on 5 May 2014 I have collected information from observers involved to document the passage and try and draw conclusions.

At Seaford, where coverage was from 05:00 to 20:00, a total of 133 were noted.  These are listed in Table 1.  Passage was slow to start (only two definites by 09:00) but picked up and continued throughout the day with few gaps of more than 30 minutes and none of more than 50 between sightings.  Despite a site (county?) record day total the largest flock was of just 11 birds.

A final thought is that at least 150 different Pomarine Skuas were recorded along the Sussex coast on 5 May 2014.  133 at Seaford, at least 15 different ones at Birling and at least 3 at Selsey (details below).

Table 1.  Pomarine Skua times off Splash Point, Seaford on 5 May 2014

time	number	morph	comment
06:10	[1]	pale	some uncertainty about a tail-less bird
07:53	1	pale
08:52	1	pale
09:14	1	pale
09:23	1	pale	possibly the same as 09:14?
09:29	9	all pale	I might not have seen the last one [-1]
09:40	10	all pale
09:59	10	9pale1?
10:10	5	4pale1dark
10:16	2	all pale
10:37	7	all pale
11:15	2	1pale1dark
11:29	1	pale
11:40	1	pale
12:10	4	all pale
12:16	2	both pale	one noted by me [-1]
12:30	1	pale
12:50	1	pale
12:59	3	2pale1dark
13:26	2	both pale?	following 5 Arctics, I missed them [-2]
13:35	11	10pale1dark
13:53	10	pale
14:00	1	pale
14:10	3	pale
14:42	4	all pale?
14:52	1	pale
15:16	4	all pale
15:34	5	all pale
15:43	3	all pale
16:10	1	dark?
16:45	3	all pale
17:04	2	both pale
17:53	1	pale
18:05	1	pale	not noted by me [-1]
18:15?	4	2pale2dark	} conflicting times noted and whether
18:33?	5	4pale1dark	} both groups landed on the sea
18:50	5	all pale	one joined four on sea, flew past at 19:20
19:23	3	all pale
19:25	1	pale
19:29	1	pale
total	133		me [-5] making my total 128

Thanks to Ewan Urquhart and Simon Linington for filling in some gaps and comments on the above.  Our notes were very similar, other than a very few minor timing issues and a bit of confusion towards the end (we were all pretty fatigued by then).

Table 2.  Comparison with Pomarine Skua flocks off Seaford and Birling

time	Seaford	Birling	time	Seaford	Birling
07:53	1		12:50	1
08:52	1	1	12:59	3
09:14	1		13:12		14
09:23	1		13:26	2
09:29	9		13:35	11
09:40	10		13:44		12
09:52		13	13:53	10
09:59	10		14:00	1
10:10	5		14:04		7
10:15		12	14:10	3
10:16	2		14:26		5
10:22		4	14:42	4
10:26		1	14:50		1
10:37	7		14:52	1
10:38		3	14:55		6
10:48		1	15:05		1
10:58		9	15:16	4
10:59		3	15:25		6
11:15	2		15:34	5
11:29	1		15:40		9
11:40	1		15:43	3
12:10	4		15:51		2
12:16	2		16:07		1
12:17		8	16:10	1
12:29		1	16:35		1
12:30	1		16:45	3
12:44		2	16:55		2
by 12:45	58	58	by 17:00	110	125

Data from Birling was kindly provided by John & David Cooper.  On the face of it this table shows no direct correspondence between observations at Seaford and Birling.  None of the flocks can be tracked from Seaford to Birling and only one single could be assumed to have flown directly and then only if the Seaford bird at 14:52 was that at Birling 13 minutes later.  At first I found this very surprising as the sites are only 6.5 km (~10 minutes) away as the Pom flies.  However David Cooper suggested that the Poms might be using Kittiwakes returning to the colony at Seaford Head as a refueling stop based on their observations of Poms mugging Kittiwakes, a behaviour we witnessed several times too.  This might explain the delays in birds reaching Birling from Seaford but is perhaps not the only explanation for the apparent constantly changing composition of flocks, at least not if there was any continuity in their travelling companions.  A suggestion that Pom’s might migrate already paired isn’t really born out with a lot of infidelity apparent if they do.  Such a phenomenon (paired migration) is much more evident with migrating Mediterranean Gulls.  For Poms, at least evidenced by these sightings, it seems to be a very fluid affair with birds leaving and joining groups.

Table 3.  Pomarine Skua totals by 15 minute periods, Selesy, Seaford and Birling

	Selsey	Seaford	Birling		Selsey	Seaford	Birling
06:15-06:29	1			13:00-13:14	4		14
06:30-06:44				13:15-13:29		2
06:45-06:59				13:30-13:44	3	11	12
07:00-07:14				13:45-13:59		10
07:15-07:29				14:00-14:14		4	7
07:30-07:44				14:15-14:29			5
07:45-07:59	1	1		14:30-14:44	2	4
08:00-08:14				14:45-14:59	1	1	7
08:15-08:29	10			15:00-15:14			1
08:30-08:44	4			15:15-15:29		4	6
08:45-08:59		1	1	15:30-15:44		8	9
09:00-09:14	4	1		15:45-15:59			2
09:15-09:29		10		16:00-16:14		1	1
09:30-09:44	1	10		16:15-16:29	4
09:45-09:59		10	13	16:30-16:44			1
10:00-10:14		5		16:45-16:59		3	2
10:15-10:29	1	2	17	17:00-17:14		2
10:30-10:44		7	3	17:15-17:29	1
10:45-10:59			13	17:30-17:44	1
11:00-11:14	1			17:45-17:59	7	1
11:15-11:29		3		18:00-18:14		1
11:30-11:44	1	1		18:15-18:29
11:45-11:59	15			18:30-18:44		4
12:00-12:14		4		18:45-18:59		6
12:15-12:29		2	9	19:00-19:14	3
12:30-12:44	9	1	2	19:15-19:29		9
12:45-12:59		4		Total	74	133	125

Justin Atkinson listed the Poms seen at Selsey and sightings from Selsey, Seaford and Birling are listed in 15 minute periods in the above table.  Few clear patterns emerge although the 10 at Selsey (at 08:29, 9 pale and 1 intermediate) could have been the 10 at Seaford at 09:49 (9 pale, 1 uncertain), 1 hour 20m being a pretty good time to cover the c70 kms they would have to fly if tracking within sight of the coast (53 km/hr or 33 mph) with no Kittiwakes to distract them.  Few other links jump out of the above table as worthy of investigation although selecting 15 minute periods is entirely arbitrary and could hide some.

The tables also support the view that birds are crossing the channel all the time with sites to the east picking up birds that did not pass further west for although Seaford cumulated a higher overall total, Birling was 15 ahead when observations there were curtailed.

The last 3 recorded at Selsey could not have reached Seaford before watching stopped there at 20:00 so a county day total of at least 133 at Seaford + 15 extra at Birling + 3 extra at Selsey = 151 would be an absolute minimum.

David Cooper suggested looking at cumulative totals and speculated that the difference on observations could be explained by the 9 birds seen arriving from the south at Birling at 10:58 and 6 at 15:25.  Ignoring these cumulative totals for Seaford and Birling are shown in Table 4.

Table 4.  Cumulative totals of Pomarine Skuas considered to have been recorded at both Seaford and Birling

	Seaford	Birling		Seaford	Birling
pre 08:45	1	0	12:45-12:59	62	49
08:45-08:59	2	1	13:00-13:14	62	63
09:00-09:14	3	1	13:15-13:29	64	63
09:15-09:29	13	1	13:30-13:44	75	75
09:30-09:44	23	1	13:45-13:59	85	75
09:45-09:59	33	14	14:00-14:14	89	82
10:00-10:14	38	14	14:15-14:29	89	87
10:15-10:29	40	31	14:30-14:44	93	87
10:30-10:44	47	34	14:45-14:59	94	94
10:45-10:59	47	38	15:00-15:14	94	95
11:00-11:14	47	38	15:15-15:29	98	95
11:15-11:29	50	38	15:30-15:44	106	104
11:30-11:44	51	38	15:45-15:59	106	106
11:45-11:59	51	38	16:00-16:14	107	107
12:00-12:14	55	38	16:15-16:29	107	107
12:15-12:29	57	47	16:30-16:44	107	108
12:30-12:44	58	49	16:45-16:59	110	110

Offsetting the time at each site by various amounts suggests that birds took longer to complete the 6.5km between Seaford and Birling in the morning than the afternoon.  Looking at the differences between the cumulative totals for each fifteen minute periods is interesting.  If birds were moving directly between Seaford and Birling little differences would be expected except those caused by the arbritrary nature of using 15 minute periods.  
Squaring differences give greater significance to a few bigger differences than many smaller ones, and stops big pluses and minuses cancelling each other out (less of an issue here)

Table 5.  Square of cumulative differences between Seaford and Birling with various offsets

offset	none	15 mins	30 mins	45 mins	60 mins
total	3310	1800	1362	1910	3318
up to 12:45	2935	1529	719	599	995
after 12:45	375	271	643	1311	2323

The numbers themselves are meaningless but the smaller totals show a better correlation.  This suggests that over the course of the day assuming a 30 minute offset, i.e. a bird passing Seaford in one 15 minute period would pass Birling two 15 minute periods later (depending on the precise times this could be a difference of between 16 and 44 minutes, e.g. 10:59 v 11:15 or 10:45 v 11:29).  The lowest total/closest match for the first half of the observations was using a 45 minute offset while a 15 minute offset was closest for the second half.  Perhaps as the day wore on the Poms became less distracted by Kittiwakes?

To me this shows that Pomarine Skua passage, at least on this occasion, is not as straight forward as I had assumed.  It was however a superb day to have devoted to seawatching (very fortunate for me being sandwiched by my 25th wedding anniversary do and work).  I’m sure it will remain long in the memories of those who were there.  Particular thanks go to Ewan Urquhart, John King, Simon Linington, Matt Eade and Liam Curson who spent longest at Seaford.  Paul & Bridget James, Tony Wilson and Julian Thomas (down from Norfolk) were also notable amongst the more usual regulars. 

Thanks too to Ewan, Simon, John & David Cooper and Justin Atkinson (via Selsey blog) for details of sightings.  I’m sure we are all hoping for repeats in the coming years to see if similar patterns emerge, and to enjoy perhaps the most eagerly anticipated spectacle of Sussex seawatching.

Pomarine Skuas flying east off Splash Point, Seaford