What Do Baby Seagulls Eat? And What Not to Feed Them

Baby seagulls eat whatever their parents regurgitate for them, and in the wild that diet is dominated by marine foods: fish, crustaceans, mollusks, and marine invertebrates. Studies using stable isotope analysis of chick feathers confirm that marine resources make up the bulk of what gull chicks consume during development, often around 85% of total intake. But gull parents are opportunistic, and in urban and coastal areas, chicks may also receive scraps of human food, insects, earthworms, and other terrestrial items. If you’ve found a baby gull or are wondering whether tossing it a chip is harmless, the details matter more than you might expect.

What Parent Gulls Naturally Bring Their Chicks

Gull chicks are entirely dependent on their parents for food during the first several weeks of life. They cannot forage on their own, and they do not leave the nest area until they are nearly fledged. Both parents take turns flying out to find food, then return and regurgitate partially digested meals directly for the chick. In lesser black-backed gull colonies studied over multiple breeding seasons, marine resources contributed an average of about 85% of chick diets, with fish, crustaceans, and other sea life forming the core of what parents delivered.¹ The remaining fraction came from terrestrial sources like insects, earthworms, and occasionally human refuse.

Researchers have used stable isotope analysis of growing feathers to trace what chicks actually consumed during development, rather than relying on observations of what parents carried back. This technique works because the chemical signatures of marine and terrestrial food sources differ, and those signatures get locked into the feather as it grows.² The picture that emerges is consistent across studies: gull chicks are built, nutritionally speaking, on seafood.

The specific mix varies by species and location. Herring gulls nesting near harbors might deliver more fish scraps from fishing boats, while colonies near agricultural land incorporate more earthworms and grain. But even in mixed environments, parents seem to lean heavily on marine prey when it is available. This preference has good nutritional logic behind it, as marine foods tend to be dense in protein, fats, and micronutrients that growing chicks need.

How Chick Feeding Actually Works

If you’ve ever watched an adult gull at a nest, you may have noticed the chick pecking aggressively at the parent’s bill. This isn’t random. The classic research on herring gull chicks, dating back to Nobel laureate Niko Tinbergen’s foundational experiments, showed that the chick’s begging response is triggered by very specific visual cues on the parent’s bill. The movement of the bill, its elongated shape, its downward-pointing angle, and especially the contrasting red spot near the tip all function as signals that release the pecking behavior.³ The shape, color, and size of the parent’s head turned out to be almost irrelevant. It is the bill, and specifically that red spot, that matters.

When the chick pecks at the red spot, the parent responds by regurgitating food. Very young chicks receive a semi-liquid slurry that is easy to swallow. As they grow, the food becomes chunkier, eventually including recognizable pieces of fish or invertebrate. By the time chicks are a few weeks old, parents may drop whole or nearly whole prey items on the ground for the chick to pick up and swallow. This progression from liquid to solid mirrors the chick’s developing ability to handle and digest larger food items.

Why the Mix of Marine and Terrestrial Food Matters

You might assume that a diet closer to 100% marine would always be better for a gull chick, but the research tells a more interesting story. In one study tracking lesser black-backed gull breeding pairs across multiple years, pairs that shifted slightly toward a lower proportion of marine food in a given year actually produced heavier chicks at fledging compared to years when the same pair relied more heavily on marine resources.¹ The variation was small, up to about 6.6% change in marine contribution between years for the same pair, but the growth benefit was measurable.

This doesn’t mean terrestrial food is broadly superior. A separate study of a coastal gull population found that parents relying more heavily on terrestrial diets had lower reproductive success, and the problem appeared to be food quantity rather than quality. Parents foraging on land simply brought back less total food to the nest.⁴ So the picture is nuanced: a diet that is mostly marine but includes some terrestrial variety may produce the best outcomes, while a diet that swings too far toward land-based foods risks underfeeding the chicks simply because terrestrial foraging tends to be less efficient for gulls.

This has implications for how we think about urban gull colonies. City-nesting gulls have abundant access to human food waste, but that abundance doesn’t automatically translate into well-fed chicks. The nutritional profile and the total volume both matter.

What Not to Feed Baby Seagulls

The single most common thing people offer gulls is bread, and it is one of the worst choices for a growing chick. Bread can technically satisfy a chick’s caloric needs in the short term, but it is low in protein and deficient in the vitamins, minerals, and fatty acids that a developing gull needs.⁵ A chick raised heavily on bread is essentially getting empty calories. It may survive, but its feather development, bone growth, and overall condition will suffer compared to a chick eating fish and invertebrates.

Beyond bread, here are other foods to avoid offering baby gulls:

Chips and salty snacks: While adult gulls have salt glands that let them drink seawater and excrete excess sodium, chick salt glands are still developing. Heavily salted foods put unnecessary strain on a system that is not yet fully functional.
Processed meats: Hot dogs, deli meat, and similar items contain preservatives, excessive salt, and additives that a chick’s digestive system is not equipped to handle.
Sugary foods: Cookies, pastries, and candy offer nothing nutritionally and can cause digestive distress.
Dairy products: Like most birds, gulls do not produce lactase and cannot properly digest milk-based foods.
Raw rice or dried beans: Contrary to the myth about rice expanding in a bird’s stomach, the real issue is that these are nutritionally inappropriate and difficult for a small chick to process.

If you feel compelled to offer food to a baby gull you’ve found, small pieces of fresh fish (like whitebait or sprat), plain cooked egg, or even tinned fish in spring water (not brine) are far better options than anything from a bakery or snack bar. But in almost every case, the right course of action is to contact a wildlife rehabilitator rather than try to feed the chick yourself.

How Baby Gulls Handle Salt and Water

One of the more remarkable features of seabird biology is the salt gland, a specialized organ located above each eye that allows marine birds to drink seawater and excrete the excess salt as a highly concentrated solution. When a gull drinks seawater, sodium enters the bloodstream from the gut and the concentration of dissolved particles in the blood rises. This triggers the salt glands to secrete a sodium chloride solution that is actually more concentrated than seawater itself, effectively generating “free” fresh water that the bird’s body can use for normal functions.⁶

In chicks, salt gland function develops gradually. Very young chicks depend heavily on the water content of the regurgitated food their parents provide, which is already partially processed and contains moisture from the prey itself. As chicks mature and begin to explore their surroundings, their salt glands become increasingly capable of handling the sodium loads that come with a marine diet. This developmental timeline is one reason why feeding a very young gull chick salty human food is particularly risky: the chick’s ability to clear that sodium is limited compared to an adult bird.

The Plastic Problem

Human food isn’t the only hazard baby gulls face from our waste. Plastic pollution is a significant and growing concern. A study of yellow-legged gull pellets, the compacted balls of indigestible material that gulls regurgitate, found at least one piece of plastic in nearly 84% of samples, with polyethylene-based sheet plastic being the most common type.⁷ That is an alarmingly high rate, and it means that gull parents are routinely ingesting plastic while foraging.

There is a partial silver lining in the data. The same study found a slight decrease in the number of plastic items in pellets around the time chicks hatched, suggesting that parent gulls may adjust their foraging behavior during the breeding season to provide more digestible, less risky food to their young.⁷ Even so, plastic fragments still end up in the regurgitated meals chicks receive. For a small, rapidly growing bird, even small amounts of ingested plastic can block the digestive tract, reduce the volume of real food the stomach can hold, and leach chemical contaminants into developing tissues.

If you’re near a gull nesting area, one of the most helpful things you can do for chick survival is simply to clean up plastic litter. It won’t show up in a chick’s meal if it isn’t in the environment.

Refuse Diets and Disease Risks for Chicks

Urban and landfill-foraging gulls face another problem that cascades down to their chicks: pathogens. When parent gulls scavenge at refuse sites, they pick up bacteria that they then transmit to their young through regurgitated food. Research along the northeastern Iberian coast found that the occurrence of Campylobacter in gull chicks was directly related to how much refuse the colony consumed.⁸ Colonies closer to landfills, and colonies whose parents relied more heavily on human garbage, had higher rates of Campylobacter in their chicks.

This has two implications worth noting. For the gulls themselves, chicks colonized with pathogenic bacteria face additional health challenges during an already vulnerable developmental period. For humans, it means that urban gull populations can serve as reservoirs for foodborne pathogens. Campylobacter and Salmonella from refuse-fed gull colonies can cycle back into the human environment through gull droppings on rooftops, playgrounds, and water sources. The cycle of gulls eating our waste and then spreading the bacteria from that waste back into human spaces is a public health loop that gets surprisingly little attention.

This is another reason why feeding gulls human food, especially near nesting sites, is counterproductive. It isn’t just that the food itself is nutritionally poor. It’s that a gull population conditioned to eat human refuse becomes a more effective vector for the same bacteria that contaminate that refuse in the first place.

Angel Wing and the Bread Myth

You may have heard that feeding bread to waterfowl causes “angel wing,” a condition where the flight feathers on the wing twist outward instead of lying flat against the body. It’s a real condition that can permanently prevent a bird from flying. The concern is widespread enough that many parks now post signs warning visitors not to feed bread to ducks and geese.

The reality is more complicated than “bread causes angel wing.” Research in White Roman geese found that the incidence and severity of angel wing were driven primarily by genetic factors rather than environmental ones like stocking density or diet alone. Geese from a line genetically selected for angel wing showed significantly higher rates regardless of their living conditions, while geese from normal-winged lines had low rates even under the same management.⁹ This suggests that while diet may play a contributing role, genetics is the dominant factor.

For gull chicks specifically, angel wing is less commonly reported than in geese or ducks, but the underlying principle holds: a diet that is excessively high in carbohydrates and low in protein during the critical feather-growth period can potentially exacerbate wing deformities in birds that are already genetically predisposed. The takeaway isn’t that bread is harmless. It’s that the problem with bread is broader than one dramatic condition. Even without angel wing, a bread-heavy diet deprives a growing chick of the protein, fats, and micronutrients it needs for healthy feather, bone, and organ development.

What to Do If You Find a Baby Gull

Most baby gulls found on the ground are not actually abandoned. Gull chicks that have left the nest but aren’t yet flying, sometimes called “runners,” are a normal stage of development. They wander around the nesting area, and their parents continue to feed them. If you find a fluffy gull chick on a rooftop, sidewalk, or beach, the parents are almost certainly nearby and watching, even if you can’t see them. Approaching too closely may trigger aggressive defensive behavior from the adults.

There are situations where intervention is genuinely needed. A chick that is visibly injured, covered in oil, being attacked by predators like cats, or stuck in an enclosed space it can’t escape from does need help. In those cases, your best option is to contact a local wildlife rescue or rehabilitation center. They have the expertise and supplies to feed the chick an appropriate diet, usually involving fish-based slurry for very young birds and whole fish for older ones.

If you must provide temporary care while waiting for a rehabilitator, keep the chick in a quiet, ventilated box lined with a towel. Offer small pieces of fresh fish or plain hard-boiled egg. Provide shallow water but do not force the bird to drink. Avoid handling the chick more than necessary, as stress compounds whatever physical problem it already has. And resist the impulse to feed it anything from your own meal. The convenience food that sustains a human afternoon is, for a baby gull, a nutritional dead end.

Do Chicks Remember What They Were Fed

An interesting question that researchers have explored is whether early diet shapes a gull’s food preferences later in life. If a chick is raised on human food, does it grow into an adult that prefers human food over fish? This matters for conservation because it could mean that urban-raised gulls perpetuate a cycle of refuse foraging across generations.

At least one controlled study tested this directly with herring gull chicks and found that early-life diet did not affect the birds’ preference for fish as they matured.⁵ Regardless of what they were fed as chicks, the gulls retained a preference for fish when given a choice. This suggests that the drive to eat marine prey is deeply ingrained, not something that can be overwritten by a few weeks of chips and sandwich crusts. Urban gulls eat human food because it is abundant and easy to access, not because their palates were shaped by what their parents brought them as chicks. If marine food were equally available, the evidence suggests they would choose it.

This finding is reassuring in one respect: a generation of gulls raised in cities near landfills is not “ruined” for marine foraging. If the availability of marine resources improves, or if refuse access is managed differently, these birds and their offspring should still pivot back toward their natural diet. The innate preference for fish persists beneath the opportunistic surface behavior that makes urban gulls seem like dedicated scavengers of human leftovers.

1
PubMed Central. Small dietary changes yield growth benefits in lesser black‐backed gull chicks
2
PubMed Central. Toxoplasma gondii Infection in Seagull Chicks Is Related to the Consumption of Freshwater Food Resources
3
Behaviour. On the Stimulus Situation Releasing the Begging Response in the Newly Hatched Herring Gull Chick (Larus Argentatus Argentatus Pont.)
4
PubMed Central. Recently-adopted foraging strategies constrain early chick development in a coastal breeding gull
5
PubMed Central. Early-life diet does not affect preference for fish in herring gulls (Larus argentatus)
6
PubMed. Regulation of salt gland, gut and kidney interactions
7
Marine Pollution Bulletin. Changes in plastic ingestion by yellow-legged gulls (Larus michahellis) over the breeding season
8
PubMed Central. Influence of refuse sites on the prevalence of Campylobacter spp. and Salmonella serovars in seagulls
9
PubMed Central. Factors Affecting the Incidence of Angel Wing in White Roman Geese: Stocking Density and Genetic Selection