Glaucous-winged Gull (Larus glaucescens)

Maritrema laricola sp. n. from the intestine of the glaucous-winged gull, Larus glaucescens, differs from other species in the genus in having an elongate body, small cirrus sac, and short, curved cirrus. The life cycle of the species was followed from sporocyst stage in Littorina scutulata and Littorina sitchana, to the metacercarial stage in Hemigrapsus oregonensis and H. nudus, and to the adult in natural and experimental hosts. In experimental infections of H. oregonensis, the cercariae penetrate and develop in the gills after which they migrate to the haemocoel of the crab and encyst. The metacercariae are fully developed in from 6 to 9 weeks, and similar in size and morphology to natural infections in crabs. Excystment of the metacercariae occurs in the following cultures at 40 °C: 3% pepsin plus 1% HCl, 0.85% saline, and seawater diluted 1:4. Metacercariae live for about 3 days in diluted seawater but do not produce eggs in any of the cultures. Only immature worms were recovered from mice and newly hatched chicks when they were fed the metacercariae, but mature worms were found in natural and experimental infections of the glaucous-winged gull. In a review of the genus Maritrema, the following transfers are made: Maritrema uca Sarkisian, 1957 to the genus Mecynophallus Cable, Connor, and Balling, 1960, and Maritreminoides raminellae Dery, 1958 to Pseudospelotrema Yamaguti, 1939.

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Effect of glucose on salt gland secretion in the glaucous-winged gull, Larus glaucescens

Comparative Biochemistry and Physiology Part A Physiology ◽

10.1016/s0300-9629(76)80042-4 ◽

1976 ◽

Vol 53 (3) ◽

pp. 311-312 ◽

Cited By ~ 5

Author(s):

Maryanne Robinson Hughes

Keyword(s):

Salt Gland ◽

Gland Secretion ◽

Salt Gland Secretion ◽

Effect Of Glucose ◽

Larus Glaucescens

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Aggressive Communication By Larus Glaucescens Part Vi: Interactions of Territory Residents With a Remotely Controled, Locomotory Model

Behaviour ◽

10.1163/156853978x00125 ◽

1978 ◽

Vol 66 (3-4) ◽

pp. 223-251 ◽

Cited By ~ 20

Author(s):

John F. Stout ◽

Charles J. Amlaner

Keyword(s):

Aggressive Communication ◽

Larus Glaucescens

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Aggressive Communication By Lar Us Gla Ucescens Part I. Sound Communication

Behaviour ◽

10.1163/156853969x00387 ◽

1969 ◽

Vol 34 (1-2) ◽

pp. 29-41 ◽

Cited By ~ 16

Author(s):

John F. Stout ◽

Carl R. Wilcox ◽

Lynn E. Creitz

Keyword(s):

Sound Production ◽

Control Period ◽

Alarm Call ◽

Experimental Period ◽

Paired Comparisons ◽

Sound Communication ◽

Communicative Functions ◽

Aggressive Communication ◽

Territorial Bird ◽

Larus Glaucescens

AbstractThe communicative functions of sound production during aggressive activity were studied by playing back the choking, trumpeting, mew, alarm and yelp calls to Larus glaucescens reacting aggressively to a mirror placed within its territory or by measuring the latency of attack on a stuffed model mounted in one of the display postures involved in aggressive activity. Differences between the experimental period with sound playback, and the control period with no sound playback were analyzed statistically by means of paired comparisons t-tests. As the result of these experiments the following conclusions were reached: I. The choking sound would inhibit the entrance of an intruder when produced by the territorial bird, but when produced by the intruder would stimulate the aggressive activity of the territorial resident. 2. The mew call functions similarly to the choking call but probably represents a somewhat lesser degree of aggressiveness. 3. The trumpeting call hastens an attack by a bird outside of its territory when produced within its territory and also stimulates aggressive activity of a bird within its territory, when produced by an intruder. 4. The alarm call inhibits aggressive activity, although it is not a usual part of aggressive activity. 5. The yelp call does not effect aggressive activity.

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Hybridization between Gulls (Larus glaucescens and L. occidentalis) in the Pacific Northwest

The Auk ◽

10.1093/auk/95.3.441 ◽

1978 ◽

Vol 95 (3) ◽

pp. 441-458 ◽

Cited By ~ 9

Author(s):

Wayne Hoffman ◽

John A. Wiens ◽

J. Michael Scott

Keyword(s):

Pacific Northwest ◽

High Frequency ◽

Equilibrium System ◽

Mixed Composition ◽

Mating Patterns ◽

Hybrid Individual ◽

Breeding Populations ◽

The Pacific ◽

Wing Tip ◽

Larus Glaucescens

Abstract Interbreeding between Glaucous-winged Gulls (Larus glaucescens) and Western Gulls (L. occidentalis) occurs extensively within a 180-km zone along the Washington coast, producing a high frequency of intermediate morphs in breeding populations. We conducted intensive studies on Destruction Island, Washington, in the midst of the zone of hybridization. There over half of the breeding birds were phenotypically intergrades between pure Glaucous-winged and Western gulls in characters of iris and eye-ring coloration, mantle shade, and wing tip pattern. Mating patterns of Destruction Island gulls were assortative, individuals pairing with mates similar to themselves. Pairs composed of pure Glaucous-winged or Western gulls hatched significantly fewer eggs than pairs containing at least one hybrid individual. The greater apparent reproductive success of the intergrades would seem to be countered by the assortative mating patterns, possibly providing conditions sufficient to maintain an equilibrium system containing both pure types as well as intergrades. These conditions are explored in a simulation model that considered immigration, density-dependent fecundity, pairing and reproduction, and mortality. A stable colony of mixed composition may be maintained by a regular but small influx of pure types into the colony.

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