Birds Can Be Drawn to the Scent of Plastic

Seabirds typically feed on krill- small crustaceans at the surface of the ocean- but over the last half century or so, they have also been feeding on small bits of plastic (microplastics) that comes from trash that has been broken from exposure to UV radiation and waves. Theories have been made as to why marine animals eat plastic. Some theorized that they mistake it for food because of its small appearance, but two scientists from the University of California, Davis released a study that said otherwise. 

Many people think the birds are stupid and can't differentiate between plastic and their normal food, but Matthew S. Savoca, the paper's lead author, says that these people don't take into consideration that these birds have been trained over hundreds of thousands of years to find tiny pieces of food in the ocean. Gabrielle A. Nevitt, a professor and author of the paper, has been studying seabirds for years. She has found that these birds have a very strong sense of smell and respond to the chemical dimethyl sulfide to find their prey. This chemical is released by phytoplankton as it gets eaten by a predator or breaks down in the ocean or on shore, which signals to the birds to come eat the predator, typically krill or a relative of krill. The two scientists found that this chemical is also released when microplastics are present in the ocean. 

In their study, the scientists used plastic beads that were four to six millimeters in diameter and made of the same plastic used in bottles, bags, textiles, and other objects. After the beads had been in the water for three weeks, dimethyl sulfide was found in the water and air. The birds are using their evolutionary traits and abilities to forage in ways that is harmful to them and is causing obstruction and toxicity. The study claims that by 2050, 99% of all seabird species will have eaten plastic debris. Dr. Nevitt says that the study may have implications for marine animals besides birds, such as baleen whales who eat similar species to the birds, or sea turtles who are also attracted to dimethyl sulfide.  Mr. Savoca said that fifty years ago there was no plastic in the ocean, and now there are hundreds of millions of tons. This number is staggering, and it is scary to know that it will only continue to grow. Humans are changing the world extremely quickly and it is harming the other species that also occupy our planet. The problem with plastic in our ocean is one that may not be able to be solved and eliminated, but it can be slowed down if people are made more aware of what our waste is doing to animals. We unknowingly contribute to the pollution of our oceans every day, even by using products that contain microplastics, so education is the best possible solution to this problem.

Seabird Stress Response is Oceans Apart

Seabird at it's nest of 2 eggs.

Black-legged kittiwake

    It is an observed fact that seabirds that die young and lay more eggs are more likely to look after their chicks when times are stressful than would less-fertile, longer-lived birds.  Jannik Schultner of Norwegian University of Science and Technology and colleagues performed an experiment of implanting Atlantic and Pacific populations of the black-legged kittiwakes.  They were implanted with tubes of a hormone that is associated with food shortages known as corticosterone. 

    The Pacific populations of the seabird have less offspring and have a higher survival rate than does the Atlantic populations.  With the hormone, the Pacific seabirds abandoned their young, making them more likely to die than the Atlantic seabirds.  The Atlantic colony had the opposite effect with extra hormones added and the survival rate of the offspring increased.  It is suggested that any animals life strategies can predict their responses to stress even if short term.
   
    I thought that this article was very interesting because we know how stress effects us individually but not really how it affects animals.  Whether the stress response is short term or long term can determine the survival rate of a species, it what I have gathered from this article.

http://alaska.usgs.gov/science/biology/seabirds_foragefish/products/publications/rlki_cort_KITAYSKY.pdf
http://alaska.usgs.gov/science/biology/seabirds_foragefish/products/reports/Bering_Sea_stress_results_99/bogrep00.php