Coexistence of Lateriporus teres (Cestoda: Dilepididae) and Polymorphus phippsi (Palaeacanthocephala: Polymorphidae) in the intestine of common eider

The purpose of the research is studying the peculiarities of parasite infection of the cestodes Lateriporus teres Krabbe, 1869 (Cestoda: Dilepididae) and acanthocephalans Polymorphus phippsi Kostylew, 1922 (Palaeacanthocephala: Polymorphidae) during coexistence in the intestine of the common eider, particularly, the localization of these parasites, the activity of protein and carbohydrate metabolism enzymes on the tegument of the worms, the degree of parasite influence on the host digestion, as well as to assess total digestive activity in the gastrointestinal tract of birds infected with these helminths.Materials and methods. Using methods of biochemical analysis, the activity of digestive enzymes (protease and glycosidase) and the intensity of a digestion with the participation of these enzymes along the intestine of the common eider were determined. The digestive activity of enzymes in the body of helminthes was measured, and the intensity of membrane digestion on the surface of their tegument was estimated.Results and discussion. During coexistence, L. teres were observed mainly in the proximal parts of the intestine of the birds, P. phippsi in the distal parts. Membrane digestion, involving the action of proteases and glycosidases, occurred on the surface of the tegument of both cestodes and acanthocephalans. The protein metabolism intensity in both helminth species was nearly the same, but the glycosidase activity was higher on the tegument of L. teres. The glycosidase activity in the body of the acanthocephalans exceeded that in the cestodes strobile six times. In the intestine parts inhabited by L. teres, both protease and glycosidase activity decreased. In the intestine parts where P. phippsi parasitized, protease activity increased in the intestinal mucosa of the common eider. The total activity of protease and glycosidase along the entire length of the intestine in common eider infected with L. teres and P. phippsi was lower compared to the uninfected birds.

The 45thAnnual Report of the California Bird Records Committee: 2019 Records

From its last report through 2019, the California Bird Records Committee reached decisions on 204 records involving 225 individuals of 62 species and one species group, endorsing 176 records of 197 individuals. These include the first accepted state record of the Yellow-browed Warbler (Phylloscopus inornatus), bringing California’s total list of accepted species to 676, of which 13 represent established introductions. Other especially notable records detailed in this report include the state’s third Common Eider (Somateria mollissima), third Common Ringed Plover (Charadrius hiaticula), fourth and fifth Red-flanked Bluetail (Tarsiger cyanurus), a significant incursion of Cassin’s Sparrows (Peucaea cassinii) into the eastern Mojave Desert, and the first Spotted Redshank (Tringa erythropus) in 30 years.

STUDIES OF THE TIME BUDGET AND DAILY ACTIVITY OF COMMON EIDER SOMATERIA MOLLISSIMA DURING INCUBATION

In the Common Eider Somateria mollissima, only females incubate the clutch over a period of 25–28 days. Determining their schedule of nest absence, how long they are away, how often, and where they go can be problematic. They must also avoid nest predation while tending to their own needs. We used geolocators to investigate the behavior of incubating females on forested islands in Dolgaya Guba Bay (65°03′N, 035°47′E), White Sea, Russia. Data were obtained for 12 females: three in 2015 and 2016, four in 2017, and two in 2018. During the entire incubation period, females left their nests for the sea 12–28 times. The average duration at sea was 331.0 ± 53.8 min, including 261.1 ± 47.9 min during the darkest hours in otherwise 24-hour daylight. The patterns are similar to those of eiders nesting in lower, nonpolar latitudes, where nights are dark.