12.13. Rynchops niger: Black Skimmer http://www.ck12.org
- marsh hawks
- Norway rats
- domestic cats
- domestic dogs
- gray squirrel
- minks
- long-tailed weasels
- striped skunks
- raccoons
- red foxes
These birds’ egg-laying process lasts about eight days. Their clutch size is about four to five eggs. They are able
to mate when 48 months (male) and 36 months (female) old. Black skimmers usually mate during the end of April
until early September.
Anatomy and Physiology
This bird has a four-chambered heart that delivers oxygen for a high metabolism. They also have two respiratory
cycles, unlike mammals, who have one. The first cycle is to inhale air in posterior air sacs, then exhale from posterior
sacs. The second cycle is when the air is inhaled from the lungs to anterior air sacs, then exhaled from anterior air
sacs. These cycles happen at the same time and help remove extra body heat during flight. The black skimmer has
three parts in their digestive system: the crop, gizzard, proventriculus. The crop is a food storage for later processing
or feeding nestlings. The gizzard is a posterior muscular stomach. Its basic task is to grind food. The proventriculus
is an anterior glandular stomach that makes gastric acid and digestive enzymes. Most birds, including the black
skimmer, lack in having a good sense of smell, but their vision and hearing are good. The black skimmer is also the
only bird whose pupil has a narrow vertical slit that protects eyes from sun, sand, and water during the day.
Behavior
The black skimmer hunts for their food at night by skimming along the water until they catch something. One of
their interesting characteristics is that they never dive or swim in water because they can’t. These birds are very
social and associate with other black skimmers during the day. Most of the time these birds try to stay in group
living so they can avoid predation. Both sexes attend to their eggs during the incubation period. The black skimmers
are also monogamous, and the male protects his mates.
References
- Bailey, Dave. “What Is a Bird?” San Diego: Mission Trails Regional Park Trail Guide Training Program,
2008. - Sibley, David.The Sibley Field Guide to Birds of Western North America. New York: Knopf, 2003. Print.
- http://animaldiversity.ummz.umich.edu/accounts/Rynchops_niger
- http://eol.org/pages/1178552/details
- http://naturebytesvideo.com/bytes_A-B/black_skimmer.html
- http://www.oiseaux-birds.com/card-black-skimmer.html
- www.allaboutbirds.org/guide/Black_Skimmer/lifehistory [http://www.allaboutbirds.org/guide/Black_Skimmer/lifehistory]