scholarly journals Kleptoparasitism by Bald Eagles (Haliaeetus leucocephalus) as a factor in reducing Peregrine Falcon (Falco peregrinus) predation on Dunlin (Calidris alpina) wintering in British Columbia

2015 ◽  
Vol 129 (2) ◽  
pp. 159 ◽  
Author(s):  
Dick Dekker ◽  
Mark C. Drever
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Bald Eagle ◽  
Haliaeetus Leucocephalus ◽  
Peregrine Falcon ◽  
Fraser River ◽  
Falco Peregrinus ◽  
Bald Eagles ◽  
Calidris Alpina ◽  
Peregrine Falcons

Kleptoparasitism, or food piracy, is common in a wide range of taxa, particularly among predators, with the larger species forcing smaller species to surrender their catch. The Bald Eagle (Haliaeetus leucocephalus) is known to rob Peregrine Falcons (Falco peregrinus) of just-caught prey. We present time series of kleptoparasitic interactions between eagles and peregrines hunting Dunlin (Calidris alpina) that were wintering at Boundary Bay in the Fraser River valley, British Columbia. In 1108 hours of observation during January, intermittently between 1994 and 2014, we recorded 667 sightings of Peregrine Falcons, including 817 attacks on Dunlin resulting in 120 captures. The population of wintering Bald Eagles in the study area increased from about 200 in 1994 to 1800 in 2014, while the rate of kleptoparasitism at the expense of peregrines increased from 0.05 to 0.20. The increase in the number of Bald Eagles coincided with a decline in January sightings of Peregrine Falcons, which suggests that some falcons may have left the study area because of interference from eagles. The decrease in Peregrine Falcon numbers can be expected to have led to reduced predation risk for Dunlins. Christmas Bird Counts conducted in the Fraser River Valley have underscored the fluctuation in eagle and peregrine numbers reported here.

scholarly journals Tufted Puffins (Fratercula Cirrhata) Respond to Predation Danger During Colony Approach Flights

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 63-70
Author(s):  
BriAnne Addison ◽  
Ronald C. Ydenberg ◽  
Barry D. Smith
Keyword(s):  
Lower Risk ◽  
Risk Level ◽  
Haliaeetus Leucocephalus ◽  
Falco Peregrinus ◽  
Bald Eagles ◽  
Escape Route ◽  
Activity Rate ◽  
Level Of Activity ◽  
Peregrine Falcons ◽  
Predation Danger

AbstractIn spite of their putative importance in the evolution of certain traits (e.g., nocturnality, coloniality, cliff nesting), the effects of aerial predators on behavior of adult seabirds at colonies have been poorly investigated. We hypothesized that Tufted Puffins (Fratercula cirrhata) respond to danger posed by aerial predators by modifying their behavior to mitigate danger. We observed Tufted Puffins making repeated colony fly-ins and departures and characterized (1) the timing of this behavior, (2) the activity rate (number of birds arriving or departing), and (3) the risk-level of activity, with respect to predation danger posed by Bald Eagles (Haliaeetus leucocephalus) and Peregrine Falcons (Falco peregrinus). As we predicted, we found that Tufted Puffins (1) dilute danger by synchronizing their fly-in and departure activities, (2) reduce fly-in and departure activity rates when predators are present, and (3) switch to lower-risk fly-in activities (e.g., staying over water where they have an escape route from an aerial attack) when predators are present.Réaction de Fratercula cirrhata au Danger de Prédation au cours des Vols d'Approche de la Colonie

Bald Eagle Lead Exposure in the Upper Midwest

2014 ◽  
Vol 5 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Sarah E. Warner ◽  
Edward E. Britton ◽  
Drew N. Becker ◽  
Michael J. Coffey
Keyword(s):  
Lead Poisoning ◽  
Lead Exposure ◽  
Clinical Signs ◽  
Local Environment ◽  
Bald Eagle ◽  
Haliaeetus Leucocephalus ◽  
Upper Midwest ◽  
Bald Eagles ◽  
Potential Source ◽  
Liver Lead Concentration

Abstract In 2012, we examined lead exposure in 58 bald eagles Haliaeetus leucocephalus found dead in Iowa, Minnesota, and Wisconsin. We determined lead concentrations in livers, examined differences in exposure among ages and between sexes, and recorded clinical signs consistent with lead poisoning. Most (60%) of the bald eagles had detectable lead concentrations, and 38% of the 58 had concentrations within the lethal range for lead poisoning. We found no differences in exposure based on sex or age, but we did find an inverse relationship between body and liver mass and liver lead concentration. The high percentage of lead-exposed bald eagles encouraged us to further examine potential sources of lead in our local environment. We initiated a study on the Fish and Wildlife Service's Upper Mississippi River National Wildlife and Fish Refuge to investigate if discarded offal piles from hunter-killed deer were a potential source of lead exposure to scavenging wildlife such as the bald eagle. Radiographs showed that 36% of offal piles in our sample area contained lead fragments ranging from 1 to 107 particles per pile. Our study indicated that 1) lead exposure rates for bald eagles found dead in our Upper Midwest study area were high, 2) more than one-third of the bald eagles found dead in Iowa, Minnesota, and Wisconsin had liver lead concentrations consistent with lead poisoning, and 3) discarded offal piles from deer shot with lead ammunition can be a potential source of lead exposure for bald eagles.

scholarly journals Bald Eagles, Haliaeetus leucocephalus, Feeding on Spawning Plainfin Midshipman, Porichthys notatus, at Crescent Beach, British Columbia

2003 ◽  
Vol 117 (4) ◽  
pp. 601 ◽  
Author(s):  
Kyle Hamish Elliott ◽  
Christina L. Struik ◽  
John E. Elliott
Keyword(s):  
British Columbia ◽  
Nous Avons ◽  
Food Source ◽  
Haliaeetus Leucocephalus ◽  
Potential Importance ◽  
Bald Eagles ◽  
Porichthys Notatus ◽  
Tide Height ◽  
Consumption Rates ◽  
Plainfin Midshipman

We observed Bald Eagles feeding on Plainfin Midshipman near Crescent Beach, British Columbia, in May and June 2001 and 2002. We quantified consumption rates and eagle numbers during this period, illustrating the potential importance of this food source to breeding eagles. Tide height was the only significant factor influencing consumption rates, likely because this variable reflected the availability of midshipman prey.Nous avons observé les Pygargues à tête blanche alimenter sur les Crapauds à nageoire unie près de Crescent Beach, Colombie-Britannique, en maie et juin 2001 et 2002. Nous avons mesuré les cadences de consommation et les nombres de pygargues pendant cette période, illustrant l’importance potentielle de cette source de nourriture pour les aigles. La taille de marée était le seul facteur significatif influençant les cadences de consommation et les nombres de pygargues pendant la période d’étude, probablement parce que cette variable a reflété la disponibilité des crapauds.

RECORDS OF ADDITIONAL EUROPEAN SAWFLIES IN AMERICA AND DESCRIPTIONS OF NEW VARIETIES OF NORTH AMERICAN SPECIES

1932 ◽  
Vol 64 (11) ◽  
pp. 247-251 ◽  
Author(s):  
Herbert H. Ross
Keyword(s):  
British Columbia ◽  
North American ◽  
West Coast ◽  
River Valley ◽  
North American Species ◽  
Alnus Rubra ◽  
Fraser River ◽  
The West ◽  
New Varieties ◽  
The Common

This species has apparently been introduced in recent years and become established as a pest of the common native alder (Alnus rubra) on the west coast of Washington and British Columbia, particularly in the lower part of the Fraser River Valley. The earliest specimens I have at hand are a series of 15 females taken at White Rock, B. C., June 28, 1929, collected by Mr. G. Beall.

Neutron activation analysis of bald eagle feathers: analytical precision and sources of sampling variation

1985 ◽  
Vol 63 (12) ◽  
pp. 2707-2718 ◽  
Author(s):  
Gary R. Bortolotti ◽  
Jon C. Barlow
Keyword(s):  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Chemical Elements ◽  
The Body ◽  
Bald Eagle ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Chemical Profiles ◽  
Significant Patterns

Instrumental neutron activation analysis was used to investigate the feather chemistry of wild and captive bald eagles (Haliaeetus leucocephalus). This paper documents variation that may be attributable to method of feather collection, laundering of samples, and precision of the analysis, as well as the variability within and among feathers from different locations on the body of individual birds. For most samples, reliable estimates could be made of the concentrations of bromine, magnesium. manganese, sodium, vanadium, aluminum, chlorine, calcium, and sulphur. Iodine and copper were detected but could not be measured precisely. There were highly significant patterns of variation along the length of a single feather for most chemical elements. The vane and calamus portions of feathers differed in chemical composition and the concentrations of the elements in the two parts were not correlated. Feathers belonging to the same molt but collected several months apart had similar chemical profiles. Variation within an individual feather and among feathers from different parts of the body necessitates rigorous consistency in the method of sampling feathers. Possible explanations for the observed patterns of elemental composition are discussed.

scholarly journals Morphological Characteristics of the Sperm of the Peregrine Falcon (Falco peregrinus) during the Reproductive Season

2021 ◽  
Vol 8 (9) ◽  
pp. 169
Author(s):  
Andrea Oliveira ◽  
Felisa Martínez ◽  
Lydia Gil ◽  
Victoria Luño
Keyword(s):  
Optical Microscopy ◽  
Morphological Characteristics ◽  
Reproductive Season ◽  
Peregrine Falcon ◽  
Sperm Cells ◽  
Falco Peregrinus ◽  
Bright Field ◽  
Morphological Abnormalities ◽  
Peregrine Falcons ◽  
Initial Stage

The morphological characteristics of different sperm cells (normal, abnormal, and immature) in the peregrine falcon during the reproductive season were analysed. We also classified the main sperm defects found in semen. Semen samples were collected from mature peregrine falcons via cloacal massage and stained with Diff-Quik stain. The percentages of normal, abnormal, and immature sperm cells were determined by bright-field optical microscopy. The number of normal spermatozoa were greater at the initial stage and subsequently decreased during the middle and later stages of the reproductive season (p < 0.01). In contrast, the percentage of abnormal spermatozoa increased significantly in the middle and end stages of the reproductive season (p < 0.05), whereas the proportion of immature spermatozoa remained stable during the study. Head defects represented the greatest proportion of morphological abnormalities, followed by the defects in the tail and midpiece regions. A small percentage of multiple defects and cytoplasmic droplets were also observed in the falcon spermatozoa. The findings of this study might be important for the development of future conservation protocols for falcon sperm.

scholarly journals Enrichment Preferences of Raptors at Elmwood Park Zoo

2018 ◽  
Vol 1 (1) ◽  
pp. 21-27
Author(s):  
Elisa Tyler Tyler
Keyword(s):  
Environmental Enrichment ◽  
Well Being ◽  
Bald Eagle ◽  
Future Research ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Buteo Jamaicensis ◽  
In Captivity ◽  
Natural Enrichment

Environmental enrichment is often offered to animals in captivity to aid in enhancing quality of life by providing appropriate environmental stimuli that improve psychological and physiological well-being. Due to the limited amount of research conducted on raptors and enrichment, I sought to determine raptor preferences of enrichment types through the observation of captive bald eagles (Haliaeetus leucocephalus) and red-tailed hawks (Buteo jamaicensis) in the education department at Elmwood Park Zoo. I predicted that the raptors would interact more with natural enrichment items compared to ones that were man-made. Although results showed only the female bald eagle to interact enough with the enrichment items to gather an adequate number of observations, she was found to interact significantly more frequently with natural enrichment items compared to ones that were man-made (p 0.0001, FET). These results are not meant to infer that all female bald eagles prefer natural enrichment items over man-made ones, or that all male bald eagles and female and male red-tailed hawks do not prefer any enrichment items. Nonetheless, they justify future research on environmental enrichment preferences involving many more individuals and many more taxa to determine more appropriate enrichment regimens for captive birds of prey.

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