Machrihanish Seabird Observatory (MSBO) September Records 2016

Compiled by Eddie Maguire (Warden)

Photo of the Month

A Great Skua (juvenile) >S off MSBO on 25th

Westerly overland passage of Northern Gannets in south Argyll 2016

This month, focus was placed on obtaining additional evidence that adult Northern Gannets cross over the Kintyre peninsula (102 birds crossed over on 17 dates during August - see MSBO August Report 2016). Volunteer birders were requested to look regularly at the behaviour of birds that were very high over Campbeltown Loch. The findings of this coordinated study, organised by MSBO, were truly startling and revealed that, as in August, adult Gannets cross overland from Campbeltown Loch to Machrihanish Bay (8km) far more frequently, and in far greater numbers than was previously documented (Maguire 2015).

In the past (2007-2015), very small numbers of adult Northern Gannets were recorded flying west over Campbeltown Loch across the Kintyre peninsula to reach Machrihanish Bay (Maguire, 2015). During August / September 2016, MSBO warden organised surveillance at Campbeltown Loch (Clyde) to determine how frequently overland passage actually occurred and the number of birds involved. The results of this were

startling. Adult Gannets were, without doubt, crossing the peninsula from Clyde waters for the Atlantic far more frequently and in far greater numbers than was previously established. In addition, mobile phone contact was requested by MSBO from observers at Campbeltown when birds were seen departing west over the town. The known departure time, then arrival time at Machrihanish Bay was very soon established. Many timed arrivals at Machrihanish Bay during September revealed that most adults complete this 8km overland journey in around 9 minutes: however, some were taking 10-12 minutes in flying into a westerly gale The timed overland flights are comparable to flight speed of Gannets measured at sea by Mike Taylor / Eddie Maguire (Seatours Campbeltown) off the Mull of Kintyre in June 2006 (unpublished data). The high-speed RIB calculation (carried out many times) revealed that Gannets were capable of sustaining flight speeds of 32-33 knots (ca. 1 km per minute) in fair weather. Varying weather conditions appear to influence this to some degree (see above). For example, at 13:00hrs on 29th September, Charles Robertson phoned from the harbour at Campbeltown to alert MSBO observers that an adult was heading west over the town and flying into the face of a westerly gale. This bird was soon located flying west over the sand dunes at Machrihanish and into the bay at 13:12hrs – the flight time taken to cross 8km in a very strong headwind was a full 12 minutes (Eddie Maguire / Iomhar McMillan).

Northern Gannets (adults) off MSBO

The table below shows dates and numbers of adult Gannets crossing overland to the west at Campbeltown on an impressive total of 42 days during August / September 2016.Observers at Campbeltown = Rab Morton / Charles Robertson.NO = No observations.

Table.

Westerly passage totals of Northern Gannets >W from Campbeltown Loch to Machrihanish Bay during August / September 2016.

Date August September1st 1 152nd NO 53rd NO 104th NO 15th NO 36th NO 57th NO 58th 13 79th NO NO10th NO 211th NO 812th NO NO13th 3 1614th NO 915th 19 816th 6 1017th 5 1118th 2 819th 2 420th 2 321st NO NO22nd NO 223rd NO NO24th 1 NO25th 6 226th 3 427th 3 328th 7 529th 11 630th 7 931st 11 -

Totals 102 161

The summary of this overland passage is truly astonishing: a total of 263 adult Gannets crossed overland from Campbeltown Loch (Clyde) to Machrihanish Bay (Atlantic) on 17 dates during August and 25 dates in September.

The established overland route from Campbeltown was originally thought to be employed by adults lured by the distant sight / frenzy of large gatherings of Gannets plunge-diving into the sea for shoaling fish, 8km to the west in Machrihanish Bay. However, recent confounding observations have revealed that this does not appear to be the catalyst for all overland crossings. Many adult Gannets have now been reported crossing the peninsula when no foraging activity was apparent in Machrihanish Bay (EM / RM / IM) and most unexpectedly, birds were reported setting off for the west from Campbeltown on two dates recently during periods of very poor visibility (RM / CR September 2016). Most birds cross the peninsula singly with occasionally 2, rarely 3 and exceptionally 4 travelling over together.Prior to setting off for the west many Gannets attain great height over the head of the loch (RM / CR). On 23rd September CR commented on this...‘Today I watched an adult gaining such great height over the head of the loch that it was almost a dot in the sky before setting off hurriedly for the west’. In view of the great height involved, the frequency of the crossings and the number of adults now known to be crossing overland from Campbeltown, it is very tempting to speculate that this could also be occurring at great height over the head of many other sea lochs in Argyll, and, elsewhere in Scotland. However, to date, the Campbeltown / Machrihanish data remains the only credible verification of regular overland passage by Northern Gannets in Scotland (Forrester et al 2007. The Birds of Scotland). Also: see Maguire, E. (2015): Westerly overland passage of Northern Gannets in south Argyll 2007-2015: The Eider, Argyll Bird Club / December 2015 (No. 114).

Summary of the September...September is renowned by birders as the best month of the year for exciting seawatching. Disappointingly, a severe paucity of strong WNW winds for most of the month denied observers at MSBO the sight of thousands of seabirds within sight of the shore. Classic conditions continued to evade us when a westerly f7 gale arrived on 29th. On this date, regular species occurred during the gale including a superb passage of Red-throated Divers (67 >S / 7hrs) and a well above average showing of some very anxious-looking juvenile Northern Gannets (14).Hordes of Black-legged Kittiwakes were visible on the horizon but stubbornly, they remained there. The rest of the period was still interesting with a good variety of migrants. Passage of Red-throated Divers was most exceptional with a total of 220 >S on 19 dates. Over 100 pale-bellied Brent Geese were logged along with sightings of Pintail, Scaup, Tufted Duck, Common Scoters, Golden and Grey Plovers, Red Knots, Curlew Sandpipers, Purple Sandpiper, Whimbrel, Black-tailed Godwits, Great Skuas and a fine presence / first-rate passage of White Wagtails and Greenland Wheatears.

Red-throated Diver: an adult - still in summer plumage - >S off MSBO

A Great Skua – juvenile >S off MSBO

List of Selected Species for September

Brent GooseFirst returning birds: two adults with 2 juveniles in tow >S on 9 th. Three flocks totalling 88 >S on 28th and 2 flocks totalling 18 >S on 29th.

Brent Geese on passage

WigeonThree >S on 5th and 7>S on 6th. One off-passage 20th-22nd. One was present 27th

- 29th.

PintailThree >S on 6th, one on 15th, 2 >S on 29th and a flock of 11 female-types >S on 30th.

Tufted DuckA male was off-passage on 12th.

Greater ScaupThree >S on 12th and 2 >S on 29th.

Common ScoterSoutherly movements: one on 2nd, 6 on 6th, 7 on 9th, 8 on 25th, one on 27th, 3 on 29th. Four >N on 4th.

Red-throated DiverSoutherly movements: two on 5th, 7 on 6th, 5 on 8th, 3 on 10th, 7 on 11th, 12 on 12th, 4 on 13th, 19 / 5hrs on 16th (including two high flying loose groups of 8 and 5), 6 on 17th, one on 18th, 5 on 19th, 9 on 23rd, one on 24th, 15 / 6hrs on 25th, 5 on 26th,

22 / 5hrs on 27th (including loose groups of 7 and 4), 3 on 28th, then a whopping total of 67 / 7hrs on 29th (westerly gale): the largest loose group was 8 and then finally 27 / 7hrs on 30th.Summary of passage: during September a total of 220 birds were logged >S off MSBO on 19 dates.

Red-throated Divers – adults on passage high over the sea

Manx ShearwaterRafts of over 1,000 were well offshore on 6th: all >S later.A light horizon movement of 300 >S / 2hrs on 10th.Another very poor autumn for movements of this species.

Northern Gannet The summary of overland passage is truly astonishing: a total of 263 adult Gannets crossed overland from Campbeltown Loch (Clyde) to Machrihanish Bay (Atlantic) on 17 dates during August and 25 dates in September (CR / RM / EM / IM). At MSBO a total of 1,600 >S / 3hrs on 2nd. Southerly movements of juveniles: one on 15th, 3 on 23rd, one on 24th, 2 on 25th, 5 on 26th, 2 on 27th, one on 28th, 14 on 29th (westerly gale) and 2 on 30th. Summary of passage: 31 juveniles >S on 9 dates during mid-late September.Note - first fledging on Ailsa Craig reaches a peak in mid–late September (Forrester et al 2007). However, juveniles passing south off MSBO during September have almost certainly originated from one of 10 colonies (including St Kilda) to the north.

A juvenile Northern Gannet >S off MSBO

Hen HarrierA female / immature on 17th.

LapwingOne was off–passage all morning on 6th.

Grey PloverTwo were photographed >S well offshore on 22nd.

Golden PloverOne on 28th. Five >S on 29th.

Ringed PloverThirty >S on 29th.

Red KnotSoutherly movements: four small flocks totalling 31 on 2nd, 4 on 4th, 9 on 8th, one on 12th, 2 on 25th, 4 on 27th, one on 29th.

A rather scruffy Golden Plover off-passage after a heavy shower

Grey Plovers offshore on passage

A Red Knot off-passage

Dunlin – Photo Steve Seal

DunlinFlocks totalling 91 >S on 2nd, 8 >S on 8th, 6 on the shore 20th - 21st and 10 >S on 23rd.

SanderlingSmall flocks totalling 39 >S on 2nd. On the shore there was nine on 5 th, one on 8th, one on 15th, 60 on 21st, then 20 >S on 29th and 4 >S on 30th.

Curlew SandpiperTwo >S on 10th.

Black-tailed GodwitOne >S on 23rd and 2 >S on 27th.

WhimbrelOne on 12th.

RedshankSoutherly passage totals: flock 12 on 1st, flocks totalling 34 on 2nd, a single flock of 26 on 7th, flock 17 on 8th. Small numbers present to 19th then 40 >S on 20th.

Common SnipeOne on 17th.

Common SandpiperNo records!

Purple SandpiperThe first bird of autumn >S on 27th.

Ruddy TurnstoneSoutherly movements: five on 6th, 11 on 8th, 31 on 10th. Ones and twos regular on the shore all month.

Great SkuaTwo >S on 25th.

Black-legged kittiwakeA total of 700 >S 6hrs on 6th. Aged samples totalling (314 birds) revealed that around 45% were juveniles. A total of 380 >S / 4hrs on 10th. Aged samples (190 birds) revealed that only 21% were juveniles.

Sandwich TernThree >S on 5th, 5 >S on 11th, one >S on 12th and 4 >S on 27th. Common TernSingle adults >S on 6th and 11th.

Black Guillemot

Regular small numbers on the sea: max 9 on 6th.

White WagtailTwenty-five on the shore on 5th. Between Machrihanish village and MSBO there was a total 42 birds on 6th. On 7th, a total of 18 >S during the morning. Most rested on the point briefly before moving on. Heavy passage occurred again on 8th with total of ca. 50+ in the Machrihanish area. Fewer (<10 per day) were present 9th – 20th. Around 20 were in the area on 22nd-25th. Singles on 26th and 30th. Pied Wagtails were present in good numbers too with ca. 100 roosting at Machrihanish Water on 8th.

Greenland WheatearTwo arrived on 4th. A total of 30+ / 5hrs passed >S on 5th. Most rested on the point briefly before continuing S. Following this peak there was 6 on 6 th, 10+ on 7th, 14 on 8th, 8 on 9th, 5 on 10th, 7 on 11th, 9 on 12th, 6 on 13th, 2 on 14th, one 18th – 20th, 2 on 21st, one on 23rd, 3 on 25th, one on 27th and one on 30th.Almost certainly one of the most protracted movements recorded here.

A White Wagtail – impressive numbers passed south this month

A juvenile Greenland Wheatear LinnetFour were by the feeding station on 14th.

TwiteThere was a very late arrival of passage birds this autumn. The first 4 were by the feeding station on 9th and by 30th an extremely poor total of only 22 were trapped / ringed.

August Records from around Kintyre

Whooper SwanStrath Farm / The Laggan: 5 adults >W on 30th.

Greylag GooseStrath Farm / The Laggan: 80-90 were present on 7th.

OspreyArdnacross (just N of Peninver): one on 8th (Miriam Lord / Dan Snowdon).

Ruddy TurnstoneCampbeltown: on 14th a flock of 63 birds were seen leaving the loch and flying high over the town to the west (Rab Morton).

Greenshank

Campbeltown Loch: 2 were at the ‘stinky hole’ on 9th (Steve / Tracy Seal).

Greenshank – Photo Steve Seal

Bar-tailed Godwit Killegruar Campsite (Glenbarr): one on 8th (Miriam Lord / Dan Snowdon).

Greenland WheatearKillegruar Campsite (Glenbarr): 5 + by the shore on 8th (Miriam Lord / Dan Snowdon) with 7 there on 13th followed by 2 on 23rd, 3 on 26th and one on 27th (Pip Ashley).Machrihanish Holiday Park: four on 20th (Martin Conway).

Snow BuntingCarradale Bay: 15 on 6th (Jill Pearson). By Campbeltown Airport: a female-type was flushed from the roadside on 8 th

(Steve / Tracy Seal).

A few more Photographs from MSBO...

Eddie Maguire (MSBO warden) Rab Morton (Sanda Island BO warden)

Tracy / Steve Seal at MSBO

Greenland Wheatear – A fresh juvenile

MSBO September 2016

A juvenile Greenland Wheatear – photo Steve Seal

Curlew

A Small Tortoiseshell sunning on Grey Scales lichen

A Painted Lady – many were seen late May - September