# Field observations of seabirds and harbour seals on Borgarey and Klakkur, Ísafjarðardjúp, Iceland

David Pierre Miles-Gaches

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David Pierre Miles-Gaches. Field observations of seabirds and harbour seals on Borgarey and Klakkur, Ísafjarðardjúp, Iceland. 2025, pp.3. hal-05369837

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https://hal.science/hal-05369837v1

Submitted on 17 Nov 2025

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Distributed under a Creative Commons Attribution 4.0 International License
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**David Pierre Milesi-Gaches**<fnref n="1" /> | Department of zoology, University of South Bohemia in České Budějovice

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https://orcid.org/0000-0002-0605-7038

# Field observations of seabirds and harbour seals on Borgarey and Klakkur, Ísafjarðardjúp, Iceland

## Context

Borgarey is a small island in Ísafjarðardjúp with restricted access and few recent ornithological observations, with only one Atlantic puffin (*Fratercula arctica*) colony estimate dating from 2014 (Náttúrufræðistofnun, 2016). The visit focused on documenting black guillemot (*Cepphus grylle*) nesting sites on Borgarey and the nearby islet Klakkur. This note reports the additional opportunistic observations collected during the short authorised landing and boat-based perimeter visit on 16 June 2025.

## Methods

Access to Borgarey was arranged by small boat in the morning, followed by a perimeter tour and a landing on the Klakkur islet. Species detections and counts were recorded during the visit, and no attempt was made to survey all sectors systematically. Visual observations were taken from land, from the boat, and from a moored sailboat, where 360° photographs were collected for later analysis. No Atlantic puffins were counted in the field; individuals were identified later exclusively from the 360° photographs, following the photographic approach described in Miles-Gaches & Lhériau-Nice (2025). The numbers presented represent minimum observable counts and should be interpreted accordingly.

## Results & conclusion

A total of 38 harbour seals (*Phoca vitulina*) were counted along the coastline of Borgarey during the perimeter boat tour (Figure 1). Due to high tide and the presence of the motorboat, only three individuals were observed hauling out, showing slight vigilance but no marked disturbance. The Arctic tern (*Sterna paradisaea*) colony was estimated at fewer than 100 individuals. A total of 148 black guillemots were counted in the field across Borgarey and Klakkur, and three additional individuals were later identified from the puffin photo inspection, close to the tern colony. Most black guillemots were observed on Klakkur, nesting in natural habitat (Figure 2), while a small number were recorded near the house and nearby material on Borgarey (Figure 1). No Eurasian oystercatchers (*Haematopus ostralegus*) or common redshanks (*Tringa totanus*) were detected, whereas common eiders (*Somateria mollissima*) and various gull species were present (Table 1). Photo inspection also revealed three greylag geese (*Anser anser*) on the southern shore of Borgarey. The visit was shortened due to deteriorating sea conditions, requiring an early departure for safety.

<footnote n="1">¹ milesi.david@gmail.com</footnote>
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**Figure 1.** Overview map of Borgarey and Klakkur showing observation sites and minimum counts. (Basemap: Loftmyndir ehf). Dashed shoreline segments indicate the coastal sectors where harbour seals (*Phoca vitulina*) were observed from the boat. The anchorage marks the fixed position from which handheld 360° panoramic photographs were taken using a Canon EOS 60D equipped with a Sigma EX 70–200 mm f/2.8 APO DG HSM lens. Photographs were obtained facing a cliffed section of Borgarey and then rotating to document the surrounding seascape; completion of the rotation required briefly shifting position on deck to work around the sailboat mast and boom. Only the shoreline directly visible from sea level was captured, and areas hidden by relief remained unobservable.

<table><caption>**Table 1.** Summary of opportunistic counts recorded on Borgarey and Klakkur (16 June 2025).</caption><thead><tr><td>Species</td><td>Count | Estimate</td><td>Method</td><td>Location</td></tr></thead><tbody><tr><td>Harbour seal</td><td>38 total | 3 hauled out</td><td>Visual</td><td>Coastline</td></tr><tr><td>Arctic tern</td><td>&lt;100</td><td>Visual estimate</td><td>South West</td></tr><tr><td>Black guillemot</td><td>151*</td><td>Visual + photo</td><td>Borgarey, Klakkur</td></tr><tr><td>Atlantic puffin</td><td>4585</td><td>Photo-only</td><td>Borgarey and offshore</td></tr><tr><td>Greylag goose</td><td>3</td><td>Photo</td><td>South West</td></tr><tr><td>Eider & gulls spp.</td><td>Detected</td><td>Visual</td><td>Various</td></tr><tr><td>Oystercatcher & redshank</td><td>Not detected</td><td>Visual</td><td>-</td></tr></tbody></table>

<footnote>* Three additional individuals were detected during the photo-based count of Atlantic puffins.</footnote>
<figure><img src="image_5.png" /><figcaption>**Figure 2.** (A) Black guillemot resting on the sailboat at the anchorage on Borgarey. (B) Black guillemots observed on natural rocky habitat on Klakkur. (C) View of Borgarey from Klakkur, showing the shallow water separating both islands.</figcaption></figure>

**Acknowledgements**

I thank the custodians of Borgarey for their permission and hospitality. I am also grateful to the Arctic Lab expedition and to captain Vincent Grison for sailing support aboard Peter Pan, and to the island caretaker who provided authorised access and transport around the islands.

Miles-Gaches, D.P., Lhériau-Nice, A., 2025. A photographic approach to monitor spatial dynamics and population trends of Arctic Tern colonies in two touristic bird watching spots in the Westfjords, Iceland. Avocetta 49. https://doi.org/10.30456/avo.28523

**References**

Náttúrufræðistofnunar, 2016. Mikilvæg fuglasvæði á Íslandi (No. 55), Fjölrit.

https://utgafa.ni.is/fjolrit/Fjolrit_55.pdf

(Accessed 16 November 2025)

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This field note is part of the *Commentarii de Natura series*, a collection of descriptive field observations, shared in support of open and reproducible naturalist documentation.

© 2025 David Pierre Milesi-Gaches

This field note is licensed under a [Creative Commons Attribution 4.0 International License (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/).

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