Glaucous Gull Vs Iceland Gull: Key Differences Explained
The northern seas of the United Kingdom host two remarkable white-winged gulls that often challenge even experienced birdwatchers: the Glaucous Gull and the Iceland Gull. While these winter visitors share similar pale plumage and Arctic origins, they possess distinct characteristics that set them apart.
Did you know that despite its name, the Iceland Gull doesn’t actually breed in Iceland? Or that the Glaucous Gull stands as the second-largest gull species in the world? These fascinating birds have evolved to thrive in some of the harshest environments on Earth, making their winter appearances along British coastlines all the more special.
In this article, let’s learn the differences in their appearances, behaviours, and habitats!
Table of Contents
Key Takeaways
- Glaucous Gulls are significantly larger, measuring 62-68cm compared to Iceland Gull’s 52-60cm
- Iceland Gulls have a more gentle, dove-like appearance with a smaller, more delicate bill
- Glaucous Gulls are bulkier with a thicker, more powerful bill
- Both species are winter visitors to the UK, present from November to April
- Iceland Gulls have a higher-pitched call compared to the deeper voice of Glaucous Gulls
- Both species share similar feeding habits but Glaucous Gulls are more aggressive predators
- Juvenile Glaucous Gulls are paler than juvenile Iceland Gulls
What Is The Difference Between A Glaucous Gull And An Iceland Gull?
While both species are pale-winged gulls that visit British shores in winter, they differ significantly in size, structure, and behaviour. The Glaucous Gull is notably larger and more powerful, while the Iceland Gull presents a gentler, more delicate appearance.
Visual Differences
The most striking visual difference between these species lies in their size and structure.
Glaucous Gulls are robust birds with thick, yellow bills and a fierce expression. Their pale grey mantle and white wingtips create a commanding presence in flight. Adults display pristine white heads and underparts, while juveniles show very pale grey plumage.
Iceland Gulls, in contrast, have a distinctly gentler appearance with a rounded head and relatively small beak. Their overall structure is more delicate, with a softer expression that often draws comparison to doves. While they share the white wingtips of their larger cousin, their smaller size and more refined features make them appear more elegant in flight.
Differences In Habitat
Both species are winter visitors to UK waters, but their habitat preferences show subtle differences. Glaucous Gulls frequently patrol coastlines and harbours, comfortable in both marine and urban environments. They’re often seen around fishing ports and offshore, displaying their adaptability to various coastal settings.
Iceland Gulls tend to prefer coastal areas but are less commonly seen inland. During winter, they can be found along rocky shorelines and in harbours, but generally maintain a more discrete presence than their larger relatives.
Both species can be observed in the UK from November through April, making winter the prime time for observation.
Nests & Eggs
While neither species breeds in the UK, their nesting behaviours in their Arctic breeding grounds differ.
Glaucous Gulls nest in coastal areas and on cliffs in the high Arctic, constructing substantial nests from vegetation and other available materials. The eggs are typically olive-brown with dark spots.
Iceland Gulls breed in Greenland and Arctic Canada, choosing cliff ledges or flat ground for their nests. Their eggs are brown or pale grey and are slightly smaller than those of Glaucous Gulls, reflecting the size difference between the species.
Both typically lay 2 to 3 eggs.
Bird Calls
Voice provides another key distinguishing feature between these gulls.
Glaucous Gulls produce a deep, laughing cry that sounds more profound than typical gull calls, matching their larger size. Their vocalisations often carry a commanding presence that matches their physical stature.
Iceland Gulls, true to their more delicate nature, have higher-pitched calls that resemble those of Herring Gulls but at a higher pitch. They tend to be quieter at sea, making their vocalisations less frequently heard than those of Glaucous Gulls.
Size & Weight
The size difference between these species is one of their most reliable identifying features. Glaucous Gulls are significantly larger, measuring 62 to 68 cm in length with a wingspan of 150 to 165 cm and weighing 1 to 2 kg. This impressive size makes them one of the largest gull species globally.
Iceland Gulls are notably smaller, measuring 52 to 60 cm in length with a wingspan of 130 to 158 cm and weighing around 750 g. This size difference is particularly noticeable when the species are seen together, making it a key identification feature for birdwatchers.
SEE ALSO: Glaucous Gull Life Cycle: Nest Building To Fledging (and everything in between)
Frequently Asked Questions
The main difference lies in their size and structure. Glaucous Gulls are significantly larger and bulkier with a thick, powerful bill, while Iceland Gulls are smaller with a more delicate, dove-like appearance and a smaller bill.
Both species can be seen along UK coastlines during winter months (November to April), particularly around harbours, fishing ports, and rocky shorelines. They are more commonly spotted in northern and eastern coastal areas.
Both species are winter visitors to the UK, with numbers varying year by year. Iceland Gulls are generally considered rarer visitors, while Glaucous Gulls are seen more frequently, particularly during winter months.
