INFORMATION

The Brandt’s Cormorant is a large seabird with a slender neck and oval body from the family Phalacrocoracidae (National Park Service). The average adult bird stands 79 cm tall, which is approximately the height of a human toddler (National Park Service). A breeding adult is black overall with a distinctly blue gular pouch beneath the throat, which distinguishes the Brandt’s Cormorant from pelagic cormorants (National Park Service). The species is native to the Pacific coast of North America, ranging from southeast Alaska to Baja California (IUCN). Brandt’s Cormorants can usually be found along the rocky coastline and offshore waters (National Park Service). They typically flock together in groups, flying in long lines hovering over the water (National Park Service). These birds nest on rocky islands and cliffs, and they forage in nearshore ocean areas by diving and swimming underwater (as far as 230 feet below the surface) to lure their prey to the surface and grasp it with their bills (All About Birds). Their diet consists of a wide variety of fish, including herring, rockfish, squid, anchovy, seabass, and also some shrimp and crabs (All About Birds). The Brandt’s Cormorant has a symbiotic relationship with other seabirds and marine life, such as gulls, pelicans, and sea lions, in that they deep dive to corral schools of fish to the surface and feed alongside these other marine species (All About Birds). Therefore, they benefit others through their combined effort to find prey (All About Birds). 

According to the IUCN, the current global wild population of Brandt’s Cormorants is estimated to be 230,000 individuals (IUCN). Although the species is categorized as Least Concern on the basis of its very large range, the overall trend is decreasing and likely to continue without increased conservation efforts (IUCN).

THREATS AND CONSERVATION 

Climate change and human disturbance are the primary threats and main causes of the Brandt’s Cormorant’s decline (IUCN). Dramatic reductions in the productivity of this species have been observed following climatic extremes (IUCN). Reduced prey due to extreme ocean warming has dramatically impacted the species’ abundance in the past. Thus, temperature extremes are an ongoing concern, as they lead to stresses on the ecosystem and on the species (IUCN). 

Nest abandonment, flushing, and lower reproductive success caused by human disturbance have been observed in Brandt’s Cormorant populations (Buxton, 2017). The species is particularly sensitive to noise which is concerning in a context of ever increasing coastal development and recreational activities.(IUCN, Weigand). In fact, ornithologist Arthur Cleveland Bent observed gulls stealing eggs from a Brandt’s Cormorant’s nest because the gulls could easily startle these birds off their nests with loud noises (National Park Service). Because auditory cues play an essential role in guiding behaviors like predator avoidance, territory defense, and mating decisions, sound associated with the mere presence of human visitors alone causes behavior changes that may translate to reduced reproductive success and detrimental colony level consequences (id. At 243).   

Unsurprisingly, fireworks produce noise and light pollution that negatively affect the Brandt’s Cormorant. July fireworks displays, which inconveniently coincide with the species’ nesting season have been connected to the decline of Brandt’s Cormorant colonies in California (Bateman). These birds have been observed changing their behavior at the onset of a fireworks display, leading them to immediately take flight and abandon their nests (Weigand).

Fireworks displays are a major concern and will make future recovery of Brandt’s Cormorant colonies less likely (Weigand). There is no need to continue using fireworks along California’s coast, particularly in San Diego, which is home to a large population of Brandt’s Cormorants. Given that these birds are easily startled and their population is in decline, discontinuing the use of fireworks in the San Diego area can have an overall positive impact on this species’s future.

REFERENCES 

1. Bateman PW et al. (2023) Pacific Conservation Biology. doi:10.1071/PC22040

2. BirdLife International. 2018. Urile penicillatus. The IUCN Red List of Threatened Species 2018: e.T22696753A133800026. Accessed on 02 July 2024.

3. Brandt’s Cormorant. (n.d.) All About Birds. https://www.allaboutbirds.org/guide/Brandts_Cormorant/lifehistory 

4. Buxton, R. T., Galvan, R., McKenna, M. F., White, C. L., & Seher, V. (2017). Visitor noise at a nesting colony alters the behavior of a coastal seabird. Marine Ecology Progress Series, 570, 233-246. https://doi.org/10.3354/meps12073

5. Clayson, W. (2021, June). Brandt’s Cormorant. National Park Service. https://irma.nps.gov/DataStore/ 

6. Weigand, J. F., & McChesney, G. J. (2008). Seabird and marine mammal monitoring and response to a fireworks display at Gualala Point Island, California, Sonoma County, May to August 2007 (Unpublished report). USDI Bureau of Land Management, California State Office, Sacramento, CA.