The figures from JNCC are alarming. Gull numbers are down again, but urban ones are up – dash, no chance of some peace this summer then? Who knows what today’s schoolboys know, but maybe we do need to go to school1 to know that Herring gulls are among the most common gulls to breed in towns and cities across Scotland, for there’s a strong correlation between takeaway joints and nest sites2.
Not only Herring gulls have a higher proportion of their UK breeding population nesting in urban and inland nest sites, compared to traditional natural habitats. What is unclear is precisely what is happening – ie going wrong in those traditional habitats?
Scotland holds half of the British and Irish natural-nesting population of herring gulls, but the latest Seabird Count 2023 found that the species has declined here by 44%, with the largest declines along the west coast. The population was estimated at 100,150 pairs with a 60/40% split between man-made and other breeding sites. Herring gull is now a red listed species of conservation concern in the UK.
It can certainly feel counterintuitive that gulls—so emblematic of seaside cliffs and harbours—would be declining along the coast even as they become more common in towns and cities. In reality, there are a few overlapping factors that might explain why this is happening – some of is supported by evidence:
1. Shifts in Food Availability at Sea
- Changes in fish stocks: Many gull species in coastal areas rely on small fish or marine invertebrates. Overfishing, changing ocean temperatures, and other climate-related shifts can reduce the availability of these resources close to shore.
- Fisheries discards regulation: Historically, gulls benefited from discards thrown overboard by commercial fishing vessels. In recent years, stricter regulations on discarding unwanted fish (to promote more sustainable fishing) have meant there’s less “free food” available to scavenging seabirds.
Result: Fewer readily available resources at sea means that gulls have to look elsewhere—often inland—for more reliable food sources.
2. Habitat Changes and Disturbance
- Coastal development and disturbance: Although Scotland’s coast is relatively undeveloped compared to more urban regions, there has still been an increase in coastal tourism, recreation, and certain types of shoreline development. This can disturb nesting gulls and reduce the suitability of specific coastal breeding sites.
- Predation and competition: Some areas have seen the return or increase of natural predators (such as raptors) or rising competition with other seabird species. Even foxes and other land-based predators may reach certain coastal nesting sites more easily if human structures provide access.
Result: Gulls may see higher breeding success in city environments, where rooftops provide predator-free nesting platforms and disturbance can sometimes be lower (ironically) than on busy beaches or cliff paths.
3. Changing Coastal Conditions and Climate Impacts
- Storm damage and rising sea levels: Extreme weather events can wash away ground-nesting areas or make cliff nests more vulnerable to collapse. While the broader coastline may remain “natural,” periodic storms can take a real toll on breeding success.
- Long-term shifts in prey distribution: Warming sea temperatures can push traditional prey species farther north or into different parts of the water column, forcing gulls to travel further offshore. This added foraging distance could reduce overall breeding success if adults expend too much energy simply finding enough to eat for themselves and their chicks.
Result: Conditions are not as stable as they might appear, and year-to-year variability can weaken coastal colony numbers over time.
4. Reliable Resources in Urban Areas
- Urban feeding opportunities: urban centres, landfill sites, and even suburban areas often provide a year-round source of easily accessible food (like discarded takeaway meals, household waste, and, yes, even deliberate feeding).
- Safe nesting spots: Many gulls have discovered that rooftops mimic the relative safety of cliff ledges, keeping ground-based predators away. Urban gulls can achieve higher breeding success on these safer nest sites. In recent history I have seen fewer attempts by enterprising home owners to dissuade them.
Result: The urban environment offers gulls clearly a less variable—and for some species, marginally more secure but not risk free lifestyle compared with the increasingly challenging conditions found at the coast.
Key Takeaway (Ed. I get it now)
Although Scotland’s coasts may still appear wild and “unchanged,” gulls are highly adaptable birds that respond swiftly to even small changes in food availability and nesting success. Overfishing, tighter regulations on fish discards, increased disturbance, and climate-induced shifts in marine ecosystems can each reduce the viability of coastal nesting. Meanwhile, urban areas offer abundant alternative feeding opportunities and relatively predator-free nest sites.
These competing forces mean that while gulls might still be highly visible in our harbours and beaches, statistically, they’re declining in many traditional colonies—and the rise in city populations is partly an opportunistic response to these changing conditions.
- Yes young people are as likely as not getting their information from sites like tiktok … doh ↩︎
- Truth is I have no data for this, but the easy availability of food is definitely one of several factors like safe nesting sites and fewer predators that make urban environments to these attractive birds. ↩︎