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