Fish Feeding Behaviours P3

Species:

  • Western Gulls (Larus occidentalis)

  • Brown Pelicans (Pelecanus occidentalis)

  • Cormorants

  • Various small fish species

Behavioural Context:

  • Feeding behaviours observed along the Pacific coast (California coastlines, estuaries, beaches).

  • Interactions between species, foraging strategies, and exploitation of human activity.

Observations & Behaviours:

Western Gulls:

  • Opportunistic feeders; consume a wide variety of food.

  • Seen stealing food from other birds (kleptoparasitism).

  • Scavenge around human environments (e.g., piers, beaches).

  • Method: pick up dropped or unattended food from humans; raid trash cans and fish remains from cleaning stations.

  • Also forage in intertidal zones—dig up invertebrates.

  • Display strong adaptability to different feeding environments.

  • Can be aggressive; chase or displace other birds to secure food.

Brown Pelicans:

  • Plunge-diving technique to catch fish; spot prey from the air, then dive headfirst into water.

  • Expand throat pouch to scoop fish and water; water is drained before swallowing prey.

  • Can be seen feeding alone or in groups.

  • Often follow fishing boats or gather where fish are abundant.

  • Juvenile pelicans may beg from adults or scavenge rather than hunt effectively themselves.

  • Can lose fish to gulls or other opportunistic birds hovering nearby.

Cormorants:

  • Pursuit divers; swim underwater to chase and capture fish.

  • Use strong legs and streamlined bodies to manoeuvre below water.

  • Often surface with fish in beak, swallow it headfirst.

  • May need to adjust fish’s position before swallowing.

  • Rest or dry wings between feeding bouts.

  • Typically feed near kelp beds, piers, or rocky shores where fish are abundant.

Inter-species Interactions:

  • Gulls frequently harass pelicans and cormorants to steal food.

  • Pelicans vulnerable to food theft during and after their dives.

  • Gulls use tactics like pecking or pulling on feathers to distract and steal.

  • Cormorants also harassed on surfacing with prey.

  • High competition among seabirds; dominance hierarchies visible in feeding areas.

Human Influence:

  • Birds scavenge from human leftovers (fishing waste, food scraps).

  • Piers and fish cleaning stations are hotspots for feeding.

  • Gulls particularly adapted to human-altered environments.

  • Human activity unintentionally supports kleptoparasitism and scavenging.

Feeding Strategies Summary:

  • Western Gulls: Opportunistic, scavenging, kleptoparasitic.

  • Brown Pelicans: Plunge diving, some reliance on scavenging (especially juveniles).

  • Cormorants: Underwater pursuit predation, efficient but vulnerable to kleptoparasitism.