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Corporate CalMac

June 2019

VSAS Survey report: Kennacraig to Islay, June 8th 2019


Volunteer Seabirds At Sea (VSAS) surveys were carried out from the forward viewing platform of the Kennacraig to Islay ferry on a scheduled return crossing on June 8th 2019. Data were collected to European Seabirds At Sea (ESAS) standard, by trained volunteers, using the JNCC VSAS app to digitally record data in real time.  

Environmental conditions were excellent for surveying, with visibility recorded as good throughout. All observations were made in seastate two or three and Beaufort wind force three to six. Swell heights were generally below one metre.

A total of 120 observations were made of 14 species of seabirds (and a further two 'species groups' where identification could not be made to species level) during the dedicated survey effort. No species of marine mammal were observed. Numbers of observations and total numbers of birds and mammals recorded are presented below in Table 1.


Distribution maps

Figures 1 - 5 show the distributions of all seabird and marine mammal species recorded during the survey.


Map for June

Figure 1. Gannet observations during Kennacraig - Islay survey, June 8th 2019


Map for June

Figure 2. Seaduck observations during Kennacraig - Islay survey, June 8thth, 2019


Map for June

Figure 3. Gull observations during Kennacraig - Islay survey, June 8thth, 2019


Map for June

Figure 4. Auk observations during Kennacraig - Islay survey, June 8thth, 2019


Map for June

Figure 5. Observations of other seabird species during Kennacraig - Islay survey, June 8thth 2019




Number of observations

Total birds observed

Common gull



Common scoter



Common tern



Common eider






Great black-backed gull






Herring gull






Manx Shearwater






Red-throated diver






Black guillemot









Large gull spp



Table 1. Numbers of observations and totals recorded per species


Species accounts

See figures 1 - 5 for maps of observations


Red-throated diver (Gavia stellata)

A single red-throated diver was noted, an adult flying northwest at the southern end of the Sound of Jura


Gannet(Morus bassanus)

The most numerous species on the survey, with 47 observations totalling 93 birds. Records were aggregated to the north of Gigha, and in the Sound of Jura. 84 out of the 93 birds observed were aged as adults.


Manx Shearwater(Puffinus puffinus)

There were two observations of Manx shearwater, with one record off the south end of Jura comprising 16 individuals.


Shag(Phalacrocorax aristotelis)

A single shag was noted north of Gigha, with another at the southern end of the Sound of Jura. Both birds were adults.


Eider (Somateria mollissima)

As usual, the west end of West Loch Tarbert was the key area for common eider. 16 were noted here, the majority of which were adult males.


Common scotermelanitta nigra)

A single adult male common scoter was noted, at the west end of West Loch Tarbert. This location fits in with observations of this species from previous surveys.


Kittiwake(Rissa tridactyla)

The most numerous gull species recorded, with 11 observations totalling 13 birds. All records were from areas of more open water, such as mid channel, and at the south end of the Sound of Jura.


Common gull(larus canus)

An interesting pattern with this species appearing to replace kittiwakes in areas of less open water. Seven observations totalling eight birds all came from West Loch Tarbert and the Sound of Jura. Most birds observed were adults.


Great black-backed gull(Larus marinus)

Three records of four birds, all from the western end of West Loch Tarbert.


Herring gull (Larus argentatus)

Another species appearing to prefer the sealochs to the more open water. 11 records totalling 11 individuals all came from West Loch Tarbert or the Sound of Jura. All of the herring gulls observed were adults.


Common tern(Sterna hirundo)

A single bird was seen at the mouth of West Loch Tarbert.


Guillemot(Uria aalge)

All records of this species (13 observations totalling 28 birds) came from areas of open water, such as mid channel and north of Gigha.


Razorbill(Alca torda)

Just four records of six birds, with observations distributed similarly to those of guillemot.


Black guillemot(Cepphus grylle)

A good survey for this species with 10 observations comprising 15 individuals. Almost all records came from the Sound of Jura.




Thanks to the volunteers who gave up their time to take part in this survey - we hope this report serves as a useful reminder of your time on board! We would also like to thank the Captain and crew of the Islay ferry for welcoming the survey team on board, and Klare Chamberlain and Ruth Rice at CalMac who helped with access and other arrangements. Finally, thanks to Simon Pinder and Rob Petley-Jones at MARINElife for coordinating volunteer effort.

List for June 2019

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