Guillemot
Seabirds known for pear-shaped eggs and cliffside colonies.
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Guillemot is the common name for several seabird species in the Alcidae or auk family, part of the order Charadriiformes.[1] The tribe Alcini is composed of the two extant Uria species, the razorbill, the little auk, and the great auk (now extinct).[2]
Quick Facts
- Field
- Seabird biology
- Known for
- Pyriform eggs and cliffside breeding colonies
- Egg weight
- Around 11% of female weight
- Egg shape
- Pyriform (pear-shaped)
Facts from the source article.
Biology and range
Guillemots lay a single pyriform egg directly on a cliff edge in dense breeding colonies and do not build a nest.[3] Compared to Cepphus, guillemots possess longer, thicker bills and white bellies, and during breeding they gather in extremely dense colonies on cliff faces.[2] Guillemot eggs are pyriform, vividly colored, and weigh roughly 11% of the female's body mass, which has historically made them sought after by collectors.[2] In a controlled test, a pyriform egg remained stationary on a steep incline, whereas a more ellipsoidal egg rolled away.[4]
Guillemot chicks hatch on seaside rocky cliffs.[5] Before their wings are capable of flight, chicks depart the nest by leaping from cliffs and descending in a parachute-like manner.[5] Their thick downy plumage and underdeveloped wings cushion their fall, preventing serious injury.[5]
What the specialist sources record
A 2023 Guardian article by Barkham reports that Tim Birkhead has studied Skomer's guillemots for 52 summers.[6] Birkhead observed that Skomer's guillemots recovered from 2,000 to nearly 30,000 birds, increasing by 5% each year.[6] The same article states that guillemots are long-lived, with Birkhead's oldest reaching 39, and they pair for life.[6] Birkhead's experiments showed the pyriform egg shape stops the egg slipping off narrow ledges, enabling dense nesting.[6]
Birkhead's studies show Skomer's guillemots have moved their breeding season two weeks earlier because of climate change.[6] Birkhead observed that nesting in close proximity shields eggs and chicks from gull predation.[6]
References
- Wikipedia, "Guillemot" (CC BY-SA 4.0), which cites: ; "guillemot", Oxford University Press, 2004 (original not read by us) en.wikipedia.org
- Wikipedia, "Guillemot" (CC BY-SA 4.0), which cites: Gaston, "The Auks", Oxford University Press, 1998; Birkhead, "The Most Perfect Thing: Inside (and Outside) a Bird's Egg", Bloomsbury, 2016 (we also read that source) en.wikipedia.org
- Wikipedia, "Guillemot" (CC BY-SA 4.0), which cites: Barkham, "'We've underrated what these birds can do': the secret life of Skomer's guillemots", The Guardian, 16 September 2023; "encyclopedia of LIFE", Miles Kelly, 2017, p. 291 (we also read that source) en.wikipedia.org
- Wikipedia, "Guillemot" (CC BY-SA 4.0), which cites: Birkhead, "The pyriform egg of the Common Murre (Uria aalge) is more stable on sloping surfaces", The Auk, 22 August 2018, p. 1020–1032 (original not read by us) en.wikipedia.org
- Wikipedia, "Guillemot" (CC BY-SA 4.0), which cites: Moscato, "Why do baby guillemots jump off cliffs before they can even fly?", Earth Touch News Network, 30 March 2017 (original not read by us) en.wikipedia.org
- Barkham, "'We've underrated what these birds can do': the secret life of Skomer's guillemots", The Guardian, 16 September 2023. facts only, no text reused. theguardian.com
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Guillemot (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
More in Miscellaneous Birds
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Guillemot (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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