April 2019

VSAS Survey report: Kennacraig to Islay, April 13th 2019

Volunteer Seabirds At Sea (VSAS) surveys were carried out from the bridge of the MV Finlaggan on a scheduled return crossing between Kennacraig and Islay on April 13^th, 2019. Data was 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 mostly good for surveying, with visibility recorded as excellent. Sea state was predominantly three to five (with occasional sea states of two and six recorded) and Beaufort wind strengths were recorded as mostly between three and five. Swell heights were between one and three metres.

A total of 109 observations were made of 13 species of seabirds (and a further three 'species groups' where identification could not be made to species level) during the dedicated survey effort. No marine mammals or other megafauna were observed. Numbers of observations and total numbers of birds recorded are presented below in Table 1.

Distribution maps

Figures 1 - 11 show the distributions of all seabird species recorded during the survey.

Figure 1. Gannet observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 2.  Shag observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 3. Great northern diver observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 4. Red-throated diver and unidentified diver observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 5. Eider observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 6. Red-breasted merganser observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 7. Herring gull observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 8.  All gull spp observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 9. Guillemot observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 10.  Guillemot/razorbill observations during Kennacraig - Islay survey, April 13^th, 2019

Figure 11.  All other spp observations during Kennacraig - Islay survey, April 13^th, 2019

Table 1. Numbers of observations and totals recorded per species

Species accounts

See figures 1 - 11 for maps of observations.  

Manx Shearwater(Puffinus puffinus)

A single Manx shearwater was observed mid-channel.

Gannet(Morus bassanus)

Small numbers of gannets were observed, with 17 records comprising 19 individuals. All were recorded in flight and all were aged as adults.

Shag(Phalacrocorax aristotelis)

Five observations totalling five individuals were recorded. All but one were in the southern part of the sound of Jura.

Great northern diver (Gavia immer)

There were 12 observations totalling 14 birds in all. All were recorded in West Loch Tarbert or north of Gigha. Many birds were transitioning into breeding plumage.

Red-throated diver (Gavia stellata)

Three records of three individuals were recorded, all from West Loch Tarbert.

Eider (Somateria mollissima)

Six observations totalling 17 individuals were recorded. Most were in West loch Tarbert, with a single bird observed in the Sound of Jura.

Red-breasted merganser (Mergus serrator)

Seven records comprising 13 individuals were recorded, all from West Loch Tarbert.

Common goldeneye (Bucephala clangula)

Two birds were noted, a male and a female in close proximity in West Loch Tarbert.

Kittiwake(Rissa tridactyla)

Just four observations comprising ten birds. All were in close proximity at the southern end of the Sound of Jura.

Herring gull(Larus argentatus)

The most abundant gull species recorded, with 13 records comprising 21 birds, all observed in West Loch Tarbert.

Great black-backed gull(Larus marinus)

Five observations totalling six individual birds, with records distributed throughout the survey area.

Guillemot(Uria aalge)

The most numerous species recorded, with 15 records comprising 45 individuals. Guillemots were distributed throughout the survey area, with only the more northern parts of the Sound of Mull not returning any records. The largest aggregations of this species (and of birds identified as either guillemot or razorbill) were found in more open waters.

Black guillemot (Cepphus grylle)

Just a single observation of an adult in breeding plumage, from the southern end of the Sound of Jura

Acknowledgements

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 MV Finlaggan 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 for coordinating volunteer effort.