Evidence suggests that anxiety is associated with a shift of visual attention toward threatening stimuli in the environment, such as facial expressions (Mogg & Bradley, 1999). More recent evidence, however, indicates may be better characterized by failure to rapidly disengage system away from threat-related (Fox, Russo, Bowles, Dutton, 2001). The present study further investigates this delayed disengagement hypothesis. Results show high trait-anxious individuals, contrast low take longer...

EVANS, R. M. 1970. Parental recognition and the mew call in Black-billed gulls (Larus bulleri). Auk 87:503-513. HAARTMAN, L. vON. 1953. Was reizt den Trauerfliegenschnapper (Muscicapa hypoleuca) zu futtern? Die Vogelwarte 16:157-164. IMPEKOVEN, 1971. Calls of very young Blackheaded gull chicks under different motivational states. Ibis 113:91-96. NORTON-GRIFFITHS, 1969. The organization, control, development parental feeding Oystercatcher (Haematopus ostralegus). Behaviour 24:57-114....

In humans, coping behaviour is an action taken to soothe oneself during or after a stressful threatening situation. Some human behaviours with physiological functions also serve as behaviours, for example, comfort sucking in infants and eating adults. birds, the of preening, which has important functions, been postulated individuals situations. We combine two existing modelling approaches - logistic regression Darwinian dynamics explore theoretically how crucial function might evolve into...

Cannibalism occurs regularly across a broad range of taxa with variety ecological and evolutionary consequences. Rises in sea surface temperature (SST) have been linked to increased cannibalism some species, including polar bears (Ursus maritimus), Peruvian anchovy (Engraulis ringens), hake (Merluccius gayi peruanus), might be expected birds that depend on marine food webs for sustenance. Increased SSTs are associated lowered ocean thermoclines weakened upwellings. These changes, turn, lead...

From 1980 to 1998, Washington's Bald Eagle (Haliaeetus leucocephalus) population increased at an annual rate of 10%. Over the same time period, foraging activity Eagles marine bird breeding colonies also increased. 1993 2008, we observed foraging-related behavior on Violet Point, Protection Island. This island hosts more than 70% seabirds in inner seaways and serves as important rookery for harbor seals (Phoca vitulina). We found that (1) eagles landed frequently seal haul-out (beach) areas...

Abstract Dinosaur eggshell is abundant in the fossil record but only during last several decades has this reproductive product been considered more than a novelty. Recent work provided evidence that both whole eggs and fragmented represent rich source of information related to paleoecology dinosaur biology. In paper, we report effects environmental variables on modern fragment orientation. Non-transported fragments at hatching predation sites favoured concave-up over concave-down...

Spontaneous oscillator synchrony has been documented in a wide variety of electrical, mechanical, chemical, and biological systems, including the menstrual cycles women estrous Norway Rats (Rattus norvegicus). In temperate regions, many colonial birds breed seasonally time window set by photoperiod; some studies have suggested that heightened social stimulation denser colonies can lead to tightened annual reproductive pulse. It unknown, however, whether analog occurs birds—that is, avian...

Other| August 01, 2000 Eggshell Taphonomy at Modern Gull Colonies and a Dinosaur Clutch Site JAMES L. HAYWARD; HAYWARD 1Biology Department, Andrews University, Berrien Springs, MI 49104-0410 Search for other works by this author on: GSW Google Scholar DARLA K. ZELENITSKY; ZELENITSKY 2Department of Geology Geophysics, The University Calgary, 2500 Dr. NW, Alberta T2N 1N4, Canada DENISE SMITH; SMITH 3Biology DARLENE M. ZAFT; ZAFT JERE CLAYBURN PALAIOS (2000) 15 (4): 343–355....

Summary It was once assumed that commercially important fish make up significant portions of seal diets. As a consequence, prior to the 1970s many populations were dramatically reduced by rampant slaughtering. Today, seals and other marine mammals are valued components ecosystems their numbers carefully managed. To facilitate management, government statutes mandate systematic monitoring populations. Population estimates based on counts hauled‐out obtained aerial survey radio satellite...

In previous studies we developed a general compartmental methodology for modeling animal behavior and applied the to marine birds mammals. this study used construct system of two differential equations model dynamics territory attendance preening in gull colony on Protection Island, Strait Juan de Fuca, Washington. We found that occupancy was driven primarily by abiotic environmental conditions, including tide height, time day, solar elevation, wind speed over open water. For colony, some...

Spontaneous oscillator synchrony is a form of self-organization in which populations interacting oscillators ultimately cycle together. This phenomenon occurs wide range physical and biological systems. In rats humans, oestrous/menstrual cycles synchronize through social stimulation with pheromones acting as synchronizing signals. previous work, we showed that glaucous-winged gulls (Larus glaucescens) can lay eggs synchronously on an every-other-day schedule, increases colony density. We...

Other| April 01, 2004 Taphonomic Effects of pH and Temperature on Extant Avian Dinosaur Eggshell JERE K. CLAYBURN; CLAYBURN 1Biology Department, Andrews University, Berrien Springs, MI 49104–0410, hayward@andrews.edu Search for other works by this author on: GSW Google Scholar DENISE L. SMITH; SMITH JAMES HAYWARD * Corresponding Author Article Information Publisher: SEPM Society Sedimentary Geology Accepted: 04 Nov 2003 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print 0883-1351 PALAIOS...

Abstract Seabirds move throughout the day in changing, patchy environments as they engage various behaviors. We studied diurnal abundance dynamics of Glaucous-winged Gulls (Larus glaucescens) a habitat patch dedicated to loafing Strait Juan de Fuca, Washington. constructed three differential equation models alternative hypotheses and then used model selection techniques choose one that most accurately described system. validated on an independent data set, made priori predictions, conducted...

Dinosaurs, like modern birds, produced enormous quantities of eggshell as part the reproductive process. Sometimes this was fossilized but most commonly destroyed by weathering. The degree to which bacteria may have contributed weathering process has not been explored. In study, fresh glaucous-winged gull (Larus glaucescens) fragments were collected from surface a breeding colony in Washington, sterilized, and buried sterile soil. soil surrounding replicate experimental inoculated with...

ABSTRACT The taphonomic effects of heat and or fire on bones, conodonts, plant tissues have received much attention from paleontologists geologists, but the effect high temperatures amniote eggshell has been unknown. We compared extant avian eggshell, which is constructed primarily CaCO3 deposited within a protein matrix. Ostrich (Struthio camelus) glaucous-winged gull (Larus glaucescens) fragments were heated to up 800 °C for varying lengths time. A series dramatic color changes, similar...

Abstract Cannibalism, which functions as a life history trait in at least 1300 species of both invertebrates and vertebrates, plays important ecological evolutionary roles populations. During times low resource availability, cannibalism juveniles by adults can redirect reproductive energy to higher availability. For example, prolonged increases sea surface temperature depress marine food webs lead increased egg among glaucous‐winged gulls ( Larus glaucescens ); consumption single...

Bald eagle (Haliaeetus leucocephalus) populations in North America rebounded the latter part of twentieth century, result tightened protection and outlawing pesticides such as DDT. An unintended consequence recovery may be a negative impact on seabirds. During 1980s, few bald eagles disturbed large glaucous-winged gull (Larus glaucescens) colony Protection Island, Washington, USA, Salish Sea. Breeding numbers this rose nearly 50% during 1980s early 1990s. Beginning 1990s, dramatic increase...

ABSTRACT Ashfall from Mount St. Helens' May 18, 1980 eruption covered eggs and nests of two species colonial, ground-nesting gulls. While some members both excavated their beneath the ash, most remained buried. One year after ashfall, habitats known to contain pre-ashfall were transected ash layer was measured removed. Eggs, nests, associated materials counted. Entire hollow eggshells eggshell fragments found, as well rodent bones teeth, bird bones, beetle carapaces, vegetation. No fetal...

We constructed differential equation models for the diurnal abundance and distribution of breeding glaucous-winged gulls (<em>Larus glaucescens</em>) as they moved among nesting non-nesting habitat patches. used time scale techniques to reduce equations algebraic connected field data. The explained data a function abiotic environmental variables with $R^{2}=0.57$. A primary goal this study is demonstrate utility methodology that can be by ecologists wildlife managers understand predict daily...