May 2019

VSAS Survey report: Ullapool to Stornoway, May 11th 2019

Volunteer Seabirds At Sea (VSAS) surveys were carried out from the bridge of the MV Loch Seaforth on a scheduled return crossing between Ullapool and Stornoway on May 11^th, 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 excellent throughout. Sea state was predominantly recorded as one (with occasional sea state three recorded) and Beaufort wind strengths were recorded as one throughout. Swell heights were generally below one metre. Survey conditions don't get much better than that!

A total of 232 observations were made of 14 species of seabirds (and a further three 'species groups' where identification could not be made to species level) during the dedicated survey effort. Two species of marine mammals were observed. Numbers of observations and total numbers of birds and mammals recorded are presented below in Table 1.

Distribution maps

Figures 1 - 10 show the distributions of all seabird and marine mammal species recorded during the survey.

Figure 1. Fulmar observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 2. Gannet observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 3. Red-throated diver, shag and black guillemot observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 4. Skua and tern observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 5. Gull observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 6. Guillemot observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 7. Razorbill observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 8. Guillemot/Razorbill observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 9. Puffin observations during Ullapool - Stornoway survey, May 11th, 2019

Figure 10. Marine mammal observations during Ullapool - Stornoway survey, May 11th, 2019

Table 1. Numbers of observations and totals recorded per species

Species accounts

See figures 1 - 10 for maps of observations

Fulmar(Fulmarus glacialis)

There were 13 observations of Fulmar, totalling 24 birds. All observations were in the mid to western Minch. Due to the calm conditions, a relatively high proportion of observations related to birds recorded on the water.

Gannet(Morus bassanus)

There were 14 records of gannet comprising 57 individuals, with the largest concentrations in the western Minch, south east of Chicken Head, south east of Stornoway harbour. The majority of birds assigned a plumage code were recorded as 'adult', with one interesting record of an I4 bird. All birds recorded in flight were heading north or north west.

Shag(Phalacrocorax aristotelis)

Four shags were recorded. All were at the eastern end of the survey area, south of Priest Island and the Summer Isles.

Red-throated diver (Gavia stellata)

One bird was recorded flying north in the western Minch.

Great skua(Stercorarius skua)

Four observations of great skua, totalling 7 individuals were recorded. Observations came from near Priest Island, mid channel, and groups of two and three noted south of Chicken head.

Arctic skua (Stercorarius parasiticus)

A single observation of four birds south of Chicken Head.

Kittiwake(Rissa tridactyla)

Just four records, but with some large groups encountered, totalling 86 birds. The majority of these were south of Chicken Head, with one group of 15 mid channel.

Common gull(Larus canus)

A single observation of a single bird, south of Chicken Head.

Great black-backed gull(Larus marinus)

One observation of ten birds, in the western part of the survey area, south of Chicken Head.

Common tern (Sterna hirundo)

Groups of two and five were recorded south of Chicken Head.

Guillemot(Uria aalge)

By far the most numerous species recorded, with 121 records comprising 425 individuals. Guillemots were distributed throughout the survey area but with the highest densities showing a clear preference for mid-channel and western areas. The largest aggregation of 120 birds was south of Chicken Head, which was a hotspot on this survey.

Razorbill(Alca torda)

Again, less numerous than guillemot (28 observations of 70 birds), but with a similar distribution, with larger aggregations showing a clear preference for mid-channel and western areas.

Puffin(Fratercula arctica)

Many fewer records than in April, with 11 records of 16 birds (compared to 61 records of 97 birds in the previous month). All observations were made mid channel.

Black guillemot (Cepphus grylle)

There were three records of black guillemot, comprising three individuals. For a species usually associated with inshore habitats, it's interesting that these records were all mid channel.

Harbour porpoise (Phocoena phocoena)

Three observations comprising five individuals. All were recorded very close to the vessel, mid channel.

Grey seal (Halichoerus grypus)

Three observations comprising three individuals. Two were in the western part of the survey area and one at the mouth of Loch Broom.

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 Loch Seaforth for welcoming the survey team on board, and to Klare Chamberlain and Ruth Rice at CalMac who helped with access and other arrangements. Finally, thanks to Simon Pinder for coordinating volunteer effort.