31st July

A warm day at the Bill with a turn in weather to come hopefully might shake things up a little and drop some more birds in. On the sea today was 200 Manx Shearwater, 2 Balearic Shearwater, 65 Common Scoter, 4 Shelduck, 2 Yellow-legged Gull, 3 Teal, 14 Mediterranean Gull  and a Great Skua. On the land at the Bill there was an increase of Willow Warbler's with 70 around, also 5 Sedge Warbler, 4 Rook, 2 Grey Heron, 8 Sand Martin and singles of Wheatear, Garden Warbler, Yellow Wagtail and Stock Dove. At Ferrybridge there was 170 Mediterranean Gull, 2 Sandwich Tern, 150 Dunlin, 23 Oystercatcher, 3 Sanderling and singles of Little Ringed Plover and Whimbrel.

On the moth front at the Bill the highlight was a Devonshire Wainscot. Other immigrants included 32 Silver Y, 12 Diamond-back Moth, 6 Dark Sword-grass, 2 Rusty Dot-pearl, 2 Buff Footman and singles of Oak Hook-tip and Jersey Tiger.

Whimbrel and Oystercatchers - Ferrybridge, 31st July 2016 © Pete Saunders

And thanks to Ken Dolbear for a photo from earlier in the week of mating Chalkhill Blues:

30th July

A near calm wind overnight and light shower in the early hours of the morning had some potential for a small fall of birds today and we weren't let down. At the Bill there was 50 Willow Warbler, 10 Sedge Warbler, 2 Blackcap, 5 Rook, 15 Oystercatcher, 2 Ringed Plover, 2 Dunlin and singles of Grasshopper Warbler, Siskin, Snipe and Stock Dove. In the afternoon Hirundines started to trickle through with 164 Swallow, 21 Sand Martin and 4 House Martin. Interest in the sea came in the form of 4 Balearic Shearwater, 2 Great Skua, 4 Yellow-legged Gulls, 400 Manx Shearwater, 60 Lesser Black-backed Gulls, 2 Black-headed Gull and 34 Common Scoter. At Ferrybridge there was 211 Mediterranean Gulls, 42 Common Tern, 42 Ringed Plover, 134 Dunlin, 4 Sanderling and singles of Yellow-legged Gull, Black-tailed Godwit, Whimbrel, Turnstone and Sandwich Tern.

Immigrant moths at the Obs consisted of 6 Silver Y, 4 Rusty-dot Pearl, 5 Dark Sword Grass, 6 Diamond-back Moth and singles of  Jersey Tiger, Four-spotted Footman and  Buff Footman

Rook and Willow Warbler, Portland Bill, 30th July 2016 © Anthony Bentley

And thanks to Pete and Debby Saunders for a selection of photos of some of the action at Ferrybridge over the last couple of days; three from Pete:

...and two from Debby:

29th July

A strong westerly overnight that lingered around in the day is not what you'd call ideal conditions. Still there some birds around although not as many as in previous days. Around at the bill were 3 Balearic Shearwater, 17 Manx Shearwater, 6 Common Scoter, 9 Willow Warbler, 4 Sedge Warbler, 3 Swift and a Whimbrel. At Ferrybridge there was 130 Dunlin, 40 Ringed Plover, 5 Turnstone, 4 Sanderling, 120 Common Tern and a single Sandwich Tern.

28th July

Autumn migration feels like its starting to gather up a bit of momentum, with today being the best day for migration for some time. The highlight of today was a Cuckoo seen in top fields, elsewhere at the bill there were 14 Sedge Warbler, 12 Willow Warbler, 37 Swallow, 7 Sand Martin, 6  Swift, 11 Dunlin, 3 Common Sandpiper and singles of Grasshopper Warbler, Grey Wagtail, Wheatear, House Martin and Turnstone. A pretty standard affair on the sea with 250 Manx Shearwater, 10 Common Scoter And singles of Great Skua, Yellow-legged Gull and Black-headed Gull. Meanwhile at Ferrybridge wader numbers continue to increase with 110 Dunlin, 25 Ringed Plover, 3 Sanderling and a lonesome Redshank; a single Arctic Tern was also dropped in there.

A rather pitiful selection of immigrant moths at the Obs amounted to no more than 3 Silver Y, a Rusty-dot Pearl and a Dark Sword Grass; elsewhere, the island's second Leopard Moth was the pick of the catch at the Grove.

Little Tern, Leopard Moth and Beech-green Carpet - Ferrybridge and the Grove, 28th July 2016 © Pete Saunders (Little Tern) and Martin Cade (the moths)

...assuming Leopard Moth isn't a hitherto undetected resident somewhere off the beaten track - the only other Portland record is from Ferrybridge so today's specimen is the first recorded from the 'island' itself - this battered individual certainly pulled out all the stops and rubbed itself bare of most scales to get here.

Beech-green Carpet is one of the odder island inhabitants: a predominantly northern species, Portland remains its only Dorset site; although quite common in places on the undercliffs and quarried edges of the island we have yet to record the species in umpteen years of trapping at the Obs and today's specimen is the first from nearly four years of trapping at the Grove.

27th July

A windy start to the day had several hundred Gannets of all ages off the Bill. Also on the sea were 200 Manx Shearwater, 18 Common Scoter and singles of Balearic ShearwaterGreat Skua, Artic Skua, Mediterranean and Black-headed Gull. Highlights on the land were 7 of each Sedge and Willow Warbler also the First Garden Warbler of the Autumn. At Ferrybridge there were 69 Dunlin and 3 Sanderling.

26th July

The highlight of the day was a Short-eared Owl at the Bill. On the sea were 63 Manx Shearwater, 3 Mediterranean Gulls and a juvenile Yellow-legged Gull. There was a little more action on the land today with 9 Sedge Warblers, 7 Willow Warblers, 2 Yellow Wagtail, 2 Collard Dove  and singles of Blackcap and Common Sandpiper. Waders at Ferrybridge included 66 Dunlin and 4 Sanderling.

Immigrant moth interest at the Obs consisted of just 19 Diamond-back Moth, 3 each of Rusty-dot Pearl and Silver Y, and a single European Corn-borer; oddities from other sites included a Vestal at the Grove.

25th July

Manx Shearwaters seem to be spending most of the day feeding off the bill with 400 seen in an hour this evening. Other interest in the sea was 26 Mediterranean Gulls, 7 Black-headed Gull, 1 Yellow-legged Gull and a Balearic Shearwater. Very little on the land with 5 Sedge Warbler, 2 Stock Dove singles of Yellow wagtail and Reed Warbler. Elsewhere on the island there were 5 Sanderling, 6 Dunlin, 23 Ringed Plover and a Turnstone at Ferrybridge. In Southwell Gardens there was also the first autumn Pied Flycatcher.

On a fresher night moth numbers fell away a little although there were a few morsels of local interest, most notably a Dingy Shears at Culverwell and a Satin Beauty at Reap Lane and (the fourth and fifth island records respectively).Immigrant numbers included 28 Diamond-back Moth, 5 Silver Y, 4 Rusty-dot Pearl, 2 European Corn-borer and singles of Dog's Tooth and Cream-bordered Green Pea at the Obs; additionally, a single Vagrant Piercer was found indoors at the Obs.

Vagrant Piercer, Dingy Shears and Satin Beauty - Portland Bill and Reap Lane, 25th July 2016 © Martin Cade

...many thanks to Anthony Bentley and John Lucas for passing us the Dingy Shears and Satin Beauty respectively.

24th July

Just a quick update to give some blog credit where it's due: we're very pleased to have fobbed off (...it's not quite like that but we're going to be away on family holiday before long so somebody's got to do it!) some of the blog updates on our assistant warden, Anthony Bentley; Anthony has taken over most of the bird updates for the time being which won't go amiss as hopefully it'll give another perspective on happenings around the island. Whilst on the subject of news from the Obs we also keep getting suggestions that we ought to have a PBO Facebook page; we're not too bothered either way but we'd welcome further comments - for or against - from Obs members and others.

Whilst the consistent sunny weather was nice today normal British weather resumed with fog, drizzle, sun, wind and rain. At the Bill were 2 Sedge Warbler and singles of  Reed Warbler and Rook. The sea continued to engage much attention with Seawatcher's from the Bill seeing the more interesting seabirds including 3 Balearic Shearwaters, a Sooty Shearwater. c100 Manx Shearwater, 4 Yellow-legged Gulls, 60 Lesser Black-backed Gull, a Mediterranean Gull, 13 Common Scoter and singles of Great and Arctic Skua. At Ferrybridge there were 46 Dunlin, 100+  Mediterranean Gulls and a Yellow-legged Gull.

On a muggier night immigrant moth numbers increased a little, with 28 Diamond-back Moth, 15 Silver Y, 7 Rusty-dot Pearl, 4 Four-spotted Footman, 3 European Corn-borer and singles of Maiden's Blush, Vestal and Red Admiral butterfly caught in the Obs moth-traps.

Yellow-legged Gull and Herring Gull - Ferrybridge, 24th July 2016 © Martin Cade

23rd July

With fisherman off the Bill reporting a large increase in whitebait it was no surprise that more seabirds turned up today. Offshore were 2 Balearic Shearwater, c200 Manx Shearwater, c500 mixed gulls, 2 Sandwich Tern and a Skua sp. On the land were 4 Sedge Warblers, 3 Rooks and 2 Common Sandpiper.

The overnight moth catch took quite a hit after fog had rolled in during the early hours. Sample immigrant totals included 20 Diamond-back Moth, 5 Silver Y, 4 Rusty-dot Pearl, 3 European Corn-borer and singles of Bulrush Cosmet Limnaecia phragmitella, Vagrant Piercer, Four-spotted Footman, Dark Sword Grass and Cream-bordered Green Pea from the Obs traps, whilst another Vagrant Piercer was caught at the Grove.

22nd July

Migration momentum was barely maintained today with nothing much more than 50 Sand Martins, 3 Yellow-legged Gulls, 2 Common Sandpiper and singles of Dunlin, Redshank, Great Spotted Woodpecker, Yellow Wagtail, Reed Warbler and Blackcap on the ground or overhead at the Bill. A Balearic Shearwater was a welcome sight offshore there in a summer that's thus far pretty well drawn a blank for them; 10 Black-headed Gulls, 8 Common Scoter, 6 Manx Shearwaters and 6 Mediterranean Gulls also passed through on the sea, whilst another 76 Mediterranean Gulls were at Ferrybridge.

On the moth front there was a nice highlight in the form of Portland's first Marbled Grass-veneer Catoptria verellus caught overnight at the Grove. Variety by way of immigrants/strays elsewhere included 44 Diamond-back Moth, 7 Silver Y, 2 Cream-bordered Green Pea and singles of Rusty-dot Pearl, Buff Footman, Fen Wainscot, Dark Spectacle and Gold Spot at the Obs.

Marbled Grass-veneer - The Grove, 22nd July 2016 © Martin Cade

21st July

Today's most noteworthy event was a significant arrival of large gulls off the Bill - presumably attracted by shoaling fish although there wasn't actually a lot of evidence of them feeding whilst they were within sight of land; numbers were hard to get a full handle on but there were a minimum of 70 Lesser Black-backed Gulls, 10 Yellow-legged Gulls, 7 Black-headed Gulls and 5 Mediterranean Gulls amongst many hundreds of Herring Gulls.  Migration-wise there was precious little change at the Bill: another 50 Sand Martins, 35 Swifts and a Dunlin passed through, singles of Reed Warbler and Sedge Warbler were new on the ground and 6 Common Scoter and 3 Manx Shearwaters headed by on the sea. Ferrybridge came up with totals of 55 Dunlin, 30 Mediterranean Gulls and singles of Black-tailed Godwit and Yellow-legged Gull.

Moth interest was much reduced, with 53 Diamond-back Moth, 7 Silver Y, 2 each of Marbled Piercer, Buff Footman and Cream-bordered Green Pea, and singles of Rusty-dot Pearl and Dark Sword Grass at the Obs.

Black-tailed Godwit, Chalkhill Blue, Gatekeepers and Small Coppers - Ferrybridge and High Angle Battery, 21st July 2016 © Pete Saunders (Blackwit) and Ken Dolbear (the butterflies)

20th July

A reminder that there's an In Focus field event at the Obs between 10am and 4pm this Saturday, 23rd July.

Passerine passage picked up today with 29 Swift, 30 Swallow, 8 Sand Martin, 2 Yellow Wagtail, 2 Rooks and singles of Great Spotted Woodpecker, Sedge Warbler, Reed Warbler and a Reed Bunting. The latter being the first ever July record for the Bill. On the sea were 3 Yellow-legged Gulls, 18 Mediterranean Gulls, 5 Black-headed Gulls, 20 Common Scoter,14 Manx Shearwater and singles of Whimbrel and Dunlin.

After yesterday's heat much had been expected of overnight moth-trapping, even if the strength of the wind remained an issue. In the event conventional immigrants remained poorly represented but a good variety of infrequently recorded species of likely Continental origin put in appearances at all the trap sites; these included 15 Marbled Piercer Cydia splendana, 5 Cream-bordered Green Pea, 3 Slender Brindle and singles of Vagrant Piercer Cydia amplana, Dark Pine Knot-horn Dioryctria abietella, Maiden's Blush, Dark Spinach, Buff Footman, Oak Nycteoline and a Green-veined White butterfly at the Obs, a Fen Wainscot at Sweethill, a Dingy Shell at Reap Lane and singles of Common Groundling Teleiodes vulgella, Warted Knot-horn Conobathra repandana and White Satin at the Grove. Sample immigrant totals included 36 Diamond-back Moth, 4 Silver Y, 3 Rusty-dot Pearl, 2 European Corn-borer and a Rush Veneer at the Obs.

Warted Knot-horn, Dark Spinach and Dingy Shell - The Grove, Portland Bill and Reap Lane, 20th July 2016 © Martin Cade

19th July

A refreshing easterly wind kept the high temperatures away making fieldwork more bearable. Again the sea created most interest with 2 Yellow-legged Gulls, 12 Common Scoter, 2 Mediterranean Gulls, 6 Black-headed Gulls, 2 Dunlin a Whimbrel and a Manx Shearwater. On the land 4 of each Sand Martin and Swift went through, a Great Spotted Woodpecker remained and a Common Sandpiper was new at the Bill. Elsewhere 2 Yellow-legged Gulls were at Ferrybridge.

Despite the high temperature overnight mothing was spoilt by a combination of the full moon and a brisk easterly, with 34 Diamond-back Moth, 2 Silver Y and a Rusty-dot Pearl the only immigrants caught at the Obs.

18th July

Another searingly hot day made bearable by the light south-easterly wind. Hirundine passage carried on today with 37 Sand Martin and 17 Swift. On the land highlights were 2 Great Spotted Woodpecker and a Yellow Wagtail. Slightly more interest in the sea with 4 Yellow-legged Gull, 20 Common Scoter, 3 Shelduck, 2 "Commic" Terns, a Redshank and a Curlew. Elsewhere 2 Yellow-legged Gull at Blacknor and 15 Mediterranean Gulls, a Sanderling and 4 Little Egrets at Ferrybridge.

Moth interest came in the form of numbers rather than quality, with fresh immigrants still poorly represented. What are likely now to be home-bred Diamond-back Moths continued to increase (including 151 at the Obs) but totals at the Obs of just 6 Silver Y and singles of European Corn-borer, Rusty-dot Pearl and Dark Sword Grass were typical of immigrant numbers/variety at all the regular trap sites.

Mediterranean Gull and Yellow-legged Gulls - Ferrybridge and Portland Bill, 18th July 2016 © Pete Saunders (Med Gull), Keith Pritchard (YLGull upper) and Martin Cade (YLGull lower)

...the Yellow-legged Gulls - both of which headed north past the Obs - were two of a minimum of six about the island during the course of the morning.

17th July

Shouldn't really complain but it was a bit too hot for meaningful fieldwork at times today. The bird of the day was a Serin that popped up twice during the morning at Blacknor. Early autumn passage remained at the bitsy level, with 75 Swallows, 20 Sand Martins, 4 Grey Herons and singles of Redshank, Yellow Wagtail and Blackcap through or on the deck at the Bill, where 59 Common Scoter, 16 Manx Shearwaters and a skua sp passed by on the sea. Elsewhere, 13 Mediterranean Gulls, 3 Sanderling, a Whimbrel and a Redshank were at Ferrybridge.

Although a few relatively regular strays featured in the moth-traps, 'proper' immigrants were still thin on the ground: Diamond-back Moths continued to increase, including 77 at the Obs, but none of the other routine species managed double figure totals.

Common Tern, Little Tern, Sparrowhawk, Whitethroat and Grey Seal - Ferrybridge, Southwell and Portland Bill, 16th/17th July 2016 © Pete Sanders (the terns), Debby Saunders (Sparrowhawk) and Ted Pressey (Whitethroat and Grey Seal)

Moth-wise, the pick of the day's sightings was a second Orange-tailed Clearwing in two days; this one, which again came to Robert Payne's pheromone lure, was discovered in the Obs Quarry:

...with two found in quick succession in widely separated parts of the island it's hard to believe the species isn't a well-established resident. As far as we can recollect, previous searches have been concentrated on the Penn's Weare area where Wayfaring Tree is extremely common; perhaps those attempts didn't coincide with the main flight period, or maybe the species prefers its Wayfaring Trees amongst flowery grassland rather than thick scrub (there are only isolated trees at both Inmosthay and the Obs Quarry, whereas they're mainly tightly packed amongst other scrub at Penn's Weare).

Finally, a nice Sulphur Pearl Sitochroa palealis from yesterday. Although most likely just a transient breeder, this species had until recently looked to be getting pretty well established on Portland; however, our trap totals at the Obs have declined sharply in the last couple of years so perhaps it's fizzling out once again?

16th July

The mothing was considerably more interesting than the birding on a lovely warm, sunny day with the chief highlight being the discovery of an Orange-tailed Clearwing - a new species for Portland - at Inmosthay Quarry. Overnight trapping had come up with few immigrants - 17 Diamond-back Moth, 2 Rusty-dot Pearl and a Dark Sword Grass made up the Obs total - but there were signs of some dispersal from the mainland, including 3 Cream-bordered Green, 2 Elephant Hawk-moth, a Wood Carpet and a Barred Red at the Obs. By day, single Clouded Yellows were at the Bill and Ferrybridge.

Bird interest consisted of little more than singles of Little Ringed Plover and Reed Warbler at the Bill and 5 Sanderling at Ferrybridge.

Orange-tailed Clearwing - Inmosthay Quarry, 16th July 2016 © Martin Cade

With the larval foodplant - Wayfaring Tree - so common in places we'd always thought it odd that this species was unrecorded from Portland, but repeated searches had drawn a blank so it seemed like the species really was absent. Thanks to Robert Payne and his pheromone lures there is now this fully confirmed record and it'll be interesting to see if some other off the beaten track spots like Inmosthay also harbour populations.

15th July

The last couple of day's migration momentum dissipated today, with Sand Martins not even getting into double figures and nothing much more than singles of Redshank and Reed Warbler on the land and 10 Common Scoter through on the sea to provide further interest at the Bill. Elsewhere there were 7 Sanderling and 3 Whimbrel at Ferrybridge.

Odds and ends by way of immigrants/wanderers making it into the moth-traps included a Barred Red at Sweethil and 21 Diamond-back Moth, 3 Rusty-dot Pearl, 3 Silver Y and singles of Rush Veneer, Dark Sword Grass and Slender Brindle at the Obs

Last night's petrel-luring session at the Bill was entertaining even if it was no more productive than others have been this summer. Although only four birds were trapped it was sufficiently clear and moonlit that these and several others were easily visible as they whizzed around after being attracted in - if you're only used to seeing Storm Petrels fluttering slowly through the waves on a seawatch then the sight of them zipping around erratically in the half-light way above net height comes as quite a revelation! We've probably remarked before on how as the season advances so the birds tend to get a good deal more vocal, and that proved to be the case last night. One individual was especially noisy, giving a host of churrs and other peculiar calls as it flew about before blundering into the net; once in the hand it still wouldn't shut up so we switched off the lure for a while and recorded it with the phone whilst it was being ringed:

14th July

A nice warm, sunny day afforded more opportunity for migrants to get going. At the Bill, 65 Sand Martins were logged but there was no coverage of West Cliffs so - like yesterday - the feeling was that this total was a considerable underestimate; small numbers of Swallows were also again mingled in. Three Whimbrel and singles of Dunlin, Yellow Wagtail, Chiffchaff and Reed Warbler also cropped up there, whilst 13 Sanderling, a Great Crested Grebe and a Redshank were at Ferrybridge. Seawatching at the Bill came up with 35 Common Scoter, 3 Manx Shearwaters, 3 Black-headed Gulls and an Oystercatcher.

Obs immigrant moth totals: 24 Diamond-back Moth and 3 Silver Y.

Great Crested Grebe, Emperor Dragonfly and Marbled White - Ferrybridge, Portland Bill and Verne LNR, 14th July 2016 © Debby Saunders (GCGrebe) and Ken Dolbear (Emperor & Marbled White)

Also, many thanks to John Dadds for an update on the latest situation with the Ferrybridge Little Terns: This year looks like yet again being a fantastic year for the little terns of Chesil Beach. Breeding pairs continue to rise with 38 this year up from 33 last year. Almost all the eggs hatched with the help of the continued use of sand patches. Food supply appears to be good with several pairs laying 3 eggs and plenty of food available to the chicks. Well over 20 pairs laid their eggs in the first week of nesting at the end of May and the vast majority of chicks have now fledged with, unlike the last two years, no predation from the West Weares kestrels. It must be a good vole year! There should now be over 50 fledglings (photo of one of them below) and there could well be over 60 by the end of the season. Darvic ringing has been very successful with 13 adults and over 30 chicks ringed. One of the photos on the PBO website a couple of days ago showed a bird which was ringed as a chick last year. If this bird bred then it is most unusual as it is believed that little terns normally don’t breed until 3 or 4 years old.