Great Black-backed Gull vs Lesser Black-backed Gull

In short

The Great Black-backed Gull is the largest gull species, easily distinguished by its massive size and robust build compared to the more slender Lesser Black-backed Gull. Both species have dark backs, but the Great Black-backed Gull's back is darker and more uniformly black, while the Lesser Black-backed Gull often appears slate-gray. Observing size and back color are key to distinguishing these species in the field.

Identification tips

• Size: Look for the larger size and bulkier build of the Great Black-backed Gull.
• Back Color: Note the darker, almost black back of the Great Black-backed Gull compared to the slate-gray of the Lesser Black-backed Gull.
• Bill: The Great Black-backed Gull has a thicker, more powerful bill.
• Behavior: Observe interactions; the Great Black-backed Gull often dominates due to its size.
• Location: Consider the habitat and region; the Great Black-backed Gull is more common in northern areas.

Size

The Great Black-backed Gull is significantly larger and bulkier than the Lesser Black-backed Gull, with a more powerful bill and broader wings.

Plumage

The Great Black-backed Gull has a darker, almost black back, while the Lesser Black-backed Gull has a slate-gray back. Both have white underparts, but the Great Black-backed Gull's contrast is more pronounced.

Behaviour

Both species are opportunistic feeders, often seen scavenging. The Great Black-backed Gull is more likely to be seen dominating other gulls due to its size.

Habitat

Both species are found near coasts and large bodies of water. The Great Black-backed Gull prefers more northern and colder regions, while the Lesser Black-backed Gull is more widespread across Europe and North America.

Voice

Vocalizations are not the most reliable distinguishing feature, but the Great Black-backed Gull's calls are deeper and more resonant.