A Wilson's Storm-petrel in Devon waters at last

Just like buses after years of waiting and speculation suddenly two Wilson's Storm-petrels (WSP) are seen in Devon waters in a matter of days!

For four years I worked on and off on a commercial angling boat, fishing the Devon side of the English Channel, without a sniff of one, despite logging over 675 European Storm-petrels! This all ended in 2013 when the boat was sold as the skipper retired, but I did a write up for Devon Birds 68(1):3–13. Although I have seen three storm-petrels that fitted Wilson's shape, size and jizz from South Devon headlands (11/08/08 and very briefly 03/09/17 at Berry Head; and 30/07/17 Start Point), I felt I really needed them close enough to get upper wing covert bar and protruding feet etc, as such a rare seabird in a Devon context and let them go as storm-petrel species (most likely Wilson's).

Yet 2017 seems like an incredible year for them, with multiple sightings off SW Cornwall, Isles of Scilly and SW Ireland, surely it was going to be Devon's year! So I wanted to get out to sea and negotiated a trip on a shark fishing boat, which has kept getting cancelled! In the meantime seawatching friend Rupert Kirkwood saw one 2 miles NE of the Eddystone (we think its Devon waters!) on 13/08/17. What was even more fantastic about this record is Rupert kayaks out that far and even better managed to get photos that clearly show a Wilson's - and he's not sitting by a load of chum going in the sea to make it easy! All credit to Rupert and a truly fantastic record, should get the Carl Zeiss photo award IMO.

So finally I got to sea on a shark fishing trip on 15/08/17, given WSP had been seen over the Herd Deep (mid-channel off Guernsey and further east), my expectations were very high. After catching some fresh Mackerel for bait we hit the fishing spot off Salcombe just before 1000hrs and the two chum bags (old mushed up Mackerel) went in to attract the sharks. Conditions for me were ideal as not flat calm, with a westerly breeze, perhaps force 3, to carry the scent of the chum. It only took 15 minutes for the first European Storm-petrels (ESP) to arrive, which steadily built up (c60 seen). As the oily chum slick built and gradually extended further and further out, storm-petrels were coming in at all distances and soon the Blue Sharks were also being caught. They are put back quickly and alive I have to add.

During the day I snapped away taking photos of the ESPs attracted to slick, most were not too close and further down the slick. However, after a couple of hours the auto-focus packed up on the DSLR camera, I had an idea what it might be, but put the camera away as I was not going to start removing lenses and cleaning contacts in a salt laden atmosphere. I also took some pictures of the guys with their Blue Sharks with my Nikon V1, until the lens packed up on that (electronic aperture went). So not a good day for my equipment! Probably a fine spray of saltwater from a constantly running hose to keep landed sharks moist (while the hook is removed), was the culprit. So camera gear dead and put away that left just trusty 8x32 bins.

So to the bird. After the boat had been chumming for approximately 5 hours, at around 15:15 I spotted a larger storm-petrel with the ESPs. A Wilson's at last this far up the English Channel! Without cameras to worry about I watched through bins. I've seen Wilson's before and gradually ticked off all the features. Appearing larger than the ESPs, hand longer than arm to give a different wing shape (and straighter on rear of wing shape), rear end (body-tail) more attenuated looking than ESP. Feet projecting beyond the tail. Upperwing showing grey covert bar and underwing looking dark unlike ESPs whitish covert bar. Occasionally feeding in distinctive dancing manner and flight less fluttery, both different from the ESPs. Then we left and headed home (just when it was getting interesting), the chum bags were emptied and even more petrels came in to feed, I would have loved to stay and sorted through them all, but it wasn't my call and off we went, frustratingly leaving a load of feeding storm-petrels!

Of course the next question was whether it was Devon's waters. Skipper measured distance we were fishing as 12nm from Salcombe. Later Tom Brereton checked whether the lat/long I gave him was in the 12nm limit. It was just (see pics), so that's Devon for me. But whether Devon or not depending on your criteria, still yet another amazing record of what is an amazing year. With Atlantic Blue Fin Tuna and Striped Dolphins seen in the SW approaches (and Herd Deep for the latter), there is something clearly different going on this year, perhaps related to sea temperature.

Another thing that struck me and I've heard this said before, when chumming you must stay with the chum slick for at least 2 hours, this took 5!

Position of Wilson's Storm-petrel sighting and 12nm limit.

Position of Wilson's Storm-petrel sighting 11.49 nautical miles off Bolt Head

Thanks to Tom Brereton, for producing these two graphics for me.


   

What’s a Devon record, or not, in terms of the sea?

Yep, an old topic I know. but this little bit I wrote in Devon Birds 68(1):14 back in April 2015 suddenly got quite topical again, after Rupert Kirkwood's excellent 'at sea' sighting, with photograph of a Wilson's Storm-petrel c2 miles NE of the Eddystone Rocks (lighthouse) on 13/08/17. So here's the piece regurgitated.

Edit. On talking to Tom Bereton a long-time researcher/surveyor for MarineLife 12nm is the one to go for. This limit already is used by most conservation bodies (but not Devon Birds!) and records can be checked for distance to Devon on http://defra.maps.arcgis.com/apps/webappviewer/index.html?id=3dc94e81a22e41a6ace0bd327af4f346. 

Edit 23/02/18. DBRC reviewed the limit and went for 12nm. Good decision.

What’s a Devon record, or not, in terms of the sea?
We may see a pelagic seabird such as a passing Sooty Shearwater from Berry Head or from a boat ten miles out at sea. In both situations the bird was at sea (its natural foraging habitat) and not flying over land; it’s just the position of the observer that is ‘land-based’ or ‘at sea’. But at what point does it count as a Devon record and when not? In 2011, the Devon Birds Records Committee (DBRC) decided that point was 5 nm from the coast, and that any records beyond this would not count; they can be included in the Devon Bird Report (DBR) for interest but do not contribute to the county’s statistics. Yet a 5nm limit follows no scientific or any other logical rationale, such as limits already in place for conservation or fisheries!
A much better option would be to use a limit already in place for the UK. The most logical approach would be to include records for Devon where its coast represents the closest county within the UK Economic Exclusion Zone (which is equivalent to the UK Continental Shelf area and broadly similar to the British fishery extent, see http://defra.maps.arcgis.com/apps/webappviewer/index.html?id=3dc94e81a22e41a6ace0bd327af4f346. Off the south coast this boundary extends halfway across the English Channel to France, and in terms of conservation the UK has responsibility for this area under the Habitats Directive. This rule of thumb could be applied
to all counties with sea areas. When reporting, records could be subsequently recorded as ‘land-based’ or ‘at sea’ (when boat-based any distance from land up to this limit), but they still count as what has been seen over the sea off Devon. This could easily be represented in the DBRs by adding an ‘at sea’ row in tabulated data for more abundant species (as in DBR 2010); then ‘at sea’ and data from regular land-based watch points could be compared for seasonal variation. Even using the UK territorial waters boundary of 12 nm would make more sense than 5 nm, as this is at least a recognized limit already in place. Interestingly, prior to 2011, and perhaps wisely, no attempt was made to define a recording area for Devon’s waters. Both Tyler (2010) and Moore (1969) made no distinction of Devon’s sea area and include ‘at sea’ records. There is no consistent approach with other counties, which use a variety of options. At a national level, BBRC and BOURC consider
records from the UK Economic Exclusion Zone (as defined above). The Isles of Scilly, renowned for their pelagic birding trips (which have made several additions to the British List) include ‘at sea’ records well beyond 5 nm with no apparent problem. Under the DBRC 5-nm rule the Lundy crossing makes an interesting case. If applied, around 7 nm of this crossing would be more than 5 nm from both the mainland and Lundy, and therefore not count as Devon. In this instance. however, DBRC state that all sightings on the Lundy crossing count as Devon records – which is at odds with any other Devon boat-based sightings! If the proposed UK Economic Exclusion Zone rule was applied, this captures Lundy and its boat crossing as well as the surrounding area of sea, with no need to make a special case. In recent times, short-range pelagic trips have been made out of Brixham; however, no attempt was made to record when inside or just outside the 5-nm limit as participants were more interested in birdwatching.
It is interesting to note that in past Devon Bird Reports, sightings from the Plymouth–Santander ferry up to the Eddystone have been attributed to Devon. Under the 5-nm rule these would not count for Devon, and even if the rule of ‘closest county coast’ were to be applied, most of these records should go to Cornwall, as once the ferry has left Plymouth Sound it is actually closest to the Cornish coast. However, the Eddystone rock has long been considered part of Devon, even though actually nearer Cornwall (some 9 miles off Rame Head). So where should records from here go?
At the time the DBRC applied the 5-nm rule, a review of past ‘at sea’ records should have been made, with a list of those no longer acceptable published in the DBR so as to amend the county’s statistics. Since this appears not to have been done, it may just be simpler to use a more logical limit, as suggested above.

References
 Moore, R. 1969. The Birds of Devon. Newton Abbot: David & Charles.
Tyler, M. 2010. The Birds of Devon. DBWPS.

West Lyme Bay large shearwaters 2017 - updated

I've always found it interesting looking at the relative ratio of the two large shearwaters occurring in west Lyme Bay (or Devon). For some reason this far up the English (western) Channel, Greats usually outnumber Cory's, in terms of both numbers and number of records. So I thought as 2017 is looking like a good year for us (we can never can compete with Cornwall or W & SW Ireland!), I'd keep a tally for the ratios I have seen for west Lyme Bay this year. Updated 06/09/17.

	Cory' Shearwater	Great Shearwater
21/07/17	181	82
22/07/17	2	3
26/07/17	1	2
28/07/17	0	17
02/08/17	0	3
03/08/17	1	3
07/08/17	1	1
11/08/17	0	12
17/08/17	0	1
05/09/17	0	1
Total	186	125
Records	5	10

So far its unusual in that Cory's have outnumbered Great. But that's really just down to one big Cory's day (21/07/17). So looking at the ratio of records, I've recorded Greats on ten days and Cory's on five so far. So a better chance (x2 for me this year) of seeing Great despite the difference in numbers. Putting 2017 into perspective with other years for Devon, for me its my best year in terms of records but not numbers - I've seen larger numbers before (i.e. one off events) for both species in Devon, though its still the best year for Cory's in west Lyme Bay.

Out of interest both large shearwaters are listed a 'A' species by Devon Birds Records Committee, hence requiring a description from observers for all birds seen. It might be time to at least move them to a 'B', requiring brief notes if requested. Neither is really a rare bird in a Devon context. Perhaps what constitutes an 'A' and 'B' should be assessed using a statistical assessment inline with BBRCs approach. Yes, they are possible to miss-identify - there's a tendency to turn distant Greats into Cory's and we shouldn't be worried about using large shearwater sp., but with experience quite distant birds can be identified correctly. Recommended reading is Mike Langman's excellent guide to: Large Shearwaters at distance. Devon Birds 65(2): 32–37.

Of course views off headlands are never as good as from a boat!

Great Shearwater - West Lyme Bay

Great Shearwater - West Lyme Bay

Cory's Shearwater

Cory's Shearwater

But sometimes they're not too bad from a South Devon headland

Great Shearwater (underside) Berry Head

Great Shearwater (upperside) Berry Head

Cory's Shearwater (underside) Berry Head

Cory's Shearwater (upperside) Berry Head

Lyme Bay maritime natural area and notable species

There seems to be some confusion as where / what Lyme Bay is and a definition of its boundary! Some (e.g. BirdGuides) assume its just the sea area off Dorset (close to Lyme Regis) and therefore records are attributable to Dorset only (e.g. recently Birdguides attributed sightings from a short-range pelagic from Brixham, Devon to Dorset). However, conservationists have long been using the definition as the area of sea between Start Point (Devon) and Portland Bill (Dorset). See Natural England's  Lyme Bay Maritime Natural Area  document. Recent short-range pelagic trips from Brixham are referred to as Lyme Bay pelagics (run by NatureTrek and local guides, often posted on Devon Bird news); tend to focus on the Devon side of Lyme Bay as Brixham is the port of embarkation.

Lyme Bay

Lyme Bay is an important staging area for many seabirds, particularly through summer-autumn. It is one of the best areas in the UK to see the critically endangered Balearic Shearwater - a species in which I have taken great interest (with over 10,000 land-based sightings over the years). From participating in at sea surveys (transects of Lyme Bay / English Channel) for MarineLife and JNCC and shore based observations (e.g. SeaWatchSW / RSPB and my own ongoing study), it appears the west side of Lyme Bay is a particular hot spot. Arrival of good numbers from late July onward usually follow a period of onshore winds with a southerly to south-westerly bias, usually if good numbers first appear on the French side of the English Channel (having tracked up around Biscay). If there is a good food source present they may linger, but as with all seabird events some years are better than others.
Any of the headlands on the west side of Lyme Bay are good, perhaps Berry Head (near Brixham) being the best in terms of sightings and access (parking etc), although Portland in the east can also be very good in some years. Berry Head has another bonus, being by Brixham which has a resident fishing fleet. Balearic Shearwaters will often follow Otter (day) trawlers back in from outer Lyme Bay, often breaking away and passing close to the headland as the boats head for port. Most notably in September 2011 I witnessed the amazing sight of 63 Balearic Shearwaters behind one trawler and 54 behind the next!
As these shearwaters are at sea, sometimes distant offshore, I tend to refer to the sighting area as west Lyme Bay in terms of a conservation area.

Balearic Shearwater - Lyme Bay

The bay also hosts a small population of White-beaked Dolphins which I've been lucky to see by boat several times and occasionally (if you're very lucky) while seawatching from Berry Head.

White-beaked Dolphin - Lyme Bay