Influence of nesting Bald Eagles (Haliaeetus leucocephalus) on Common Loon (Gavia immer) occupancy and productivity in New Hampshire

10.1676/18-75 ◽  
2019 ◽  
Vol 131 (2) ◽  
pp. 329 ◽  
Author(s):  
John H. Cooley ◽  
David R. Harris ◽  
Vanessa S. Johnson ◽  
Christian J. Martin
Keyword(s):  
New Hampshire ◽  
Haliaeetus Leucocephalus ◽  
Gavia Immer ◽  
Common Loon ◽  
Bald Eagles

Relationships among mercury, selenium, and neurochemical parameters in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus)

Ecotoxicology ◽  
2007 ◽  
Vol 17 (2) ◽  
pp. 93-101 ◽  
Author(s):  
A. M. Scheuhammer ◽  
N. Basu ◽  
N. M. Burgess ◽  
J. E. Elliott ◽  
G. D. Campbell ◽  
...  
Keyword(s):  
Haliaeetus Leucocephalus ◽  
Gavia Immer ◽  
Bald Eagles ◽  
Common Loons

Water-bird population changes in 1976–1990 on Besnard Lake, Saskatchewan: increases in loons, gulls, and pelicans

1993 ◽  
Vol 71 (8) ◽  
pp. 1681-1686 ◽  
Author(s):  
Jon M. Gerrard ◽  
Elston Dzus ◽  
Gary R. Bortolotti ◽  
P. Naomi Gerrard
Keyword(s):  
Present Report ◽  
Predatory Fish ◽  
Haliaeetus Leucocephalus ◽  
Small Fish ◽  
Gavia Immer ◽  
Bald Eagles ◽  
Herring Gulls ◽  
Ardea Herodias ◽  
Pelecanus Erythrorhynchos ◽  
Human Use

Declines in Common Loon (Gavia immer) populations associated with increasing human use of lakes have been reported from many areas of North America. In the present report we describe a lake in northern Saskatchewan, Besnard Lake, where there has been a substantial increase in the number of loons, from about 85 in 1976–1979 to about 165 in 1990. A comparison was made with numbers of other birds associated with water. Increases were also seen in American White Pelicans (Pelecanus erythrorhynchos), Osprey (Pandion haliaetus), Great Blue Herons (Ardea herodias), Herring Gulls (Larus argentatus), Ring-billed Gulls (L. delawarensis), and Bonaparte's Gulls (L. Philadelphia). No change was seen in mergansers (Mergus merganser and M. serrator), Bald Eagles (Haliaeetus leucocephalus), or Common Terns (Sterna hirundo). The period 1976–1990 has also seen increased human use on Besnard Lake. The reason for increased loon numbers is uncertain, but could possibly be related to an increase in the numbers of small fish in Besnard Lake as a result of increased fishing pressure disproportionately removing the larger, predatory fish.

Common Loon (Gavia immer)

2020 ◽  
Author(s):  
David C. Evers ◽  
James D. Paruk ◽  
Judith W. McIntyre ◽  
Jack F. Barr
Keyword(s):  
Gavia Immer ◽  
Common Loon

scholarly journals Common Loon, Gavia immer, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

2009 ◽  
Vol 123 (2) ◽  
pp. 146 ◽  
Author(s):  
Robert Alvo
Keyword(s):  
Breeding Success ◽  
Low Ph ◽  
Single Pair ◽  
Gavia Immer ◽  
Common Loon ◽  
Sulphur Deposition ◽  
Acidic Lakes ◽  
Ph Range ◽  
Lake Size ◽  
Critical Ph

I monitored Common Loon (Gavia immer) breeding success in relation to lake pH (range 4.0–8.5) between 1982 and 2007 on 38 single-pair lakes (5–88 ha) in the Sudbury, Ontario, area. No chicks fledged on lakes with pH < 4.4. Chicks fledged on lakes with slightly higher pH only if the lakes were relatively large. Acidic lakes became less acidic as sulphur dioxide emissions from the Sudbury smelters and sulphur deposition from other long-range sources decreased. Two lakes initially too acidic to support successful loon reproduction eventually had successful reproduction. One loon pair used two large acidic lakes (combined area 140 ha) connected by shallow rapids, and one of the adults made extremely long dives (average = 99 s) while foraging for the chicks. One chick died on that lake after apparently ingesting a very large food item; the lack of smaller items was attributed to the lake’s acidity. My results suggest that a shortage of food for chicks is the main reason why low pH reduces breeding success. I suggest that, for lakes without high levels of dissolved organic carbon (DOC), the critical pH for loon breeding success is approximately 4.3, and the suboptimal pH is approximately 4.4–6.0.

scholarly journals Ecological interactions and habitat modification in nesting Common Murres, Uria aalge

1996 ◽  
Vol 6 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Julia K. Parrish ◽  
Robert T. Paine
Keyword(s):  
Reproductive Output ◽  
Habitat Modification ◽  
Haliaeetus Leucocephalus ◽  
Uria Aalge ◽  
Ecological Interactions ◽  
Bald Eagles ◽  
Predator Removal ◽  
Common Murre ◽  
Corvus Caurinus ◽  
Common Murres

SummarySeabird populations suffer from a variety of natural and human-induced sources of mortality and loss of lifetime reproductive output. On the outer coast of Washington State, Common Murre Uria aalge populations have been in decline for approximately the last decade and are currently reproductively active only at Tatoosh Island. These murres nest in two basic habitat types: crevices (25% of the population) and larger cliff-top subcolonies (75%). Murres in cliff-top subcolonies have suffered dramatic reductions in reproductive success in recent years relative to conspecifics nesting in the crevices, primarily due to egg predation by Glaucous-winged Gulls Larus glaucescens and Northwestern Crows Corvus caurinus, facilitated by the presence of Bald Eagles Haliaeetus leucocephalus. Because predator removal is not feasible and creation of additional crevice habitat is difficult, expensive and potentially ineffective, we have designed a temporary habitat modification (the “silk forest”) which replaces the natural vegetation cover and modifies the interaction between murres and eagles. Within the test subcolony, murres nesting under and immediately adjacent to the silk forest produced nearly twice as many eggs per square metre as their conspecifics nesting in adjacent exposed-ground areas.

Reproductive success of bald eagles (Haliaeetus leucocephalus) and its association with habitat or landscape features and weather in southeast Alaska

1997 ◽  
Vol 75 (10) ◽  
pp. 1595-1604 ◽  
Author(s):  
Scott M. Gende ◽  
Mary F. Wilson ◽  
Mike Jacobsen
Keyword(s):  
Early Spring ◽  
Average Density ◽  
Nesting Success ◽  
Egg Laying ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Active Nest ◽  
Southeast Alaska ◽  
Landscape Features

Long-term data have been collected on nesting bald eagles (Haliaeetus leucocephalus) in three areas of southeast Alaska. The average density of active nests was among the highest recorded, but nest productivity (average number of young fledged per active nest) and success (percentage of active nests that fledged at least one young) were similar to values in other areas. Using logistic regression, nest productivity was associated with several habitat or landscape features (productivity was highest in proximity to spawning herring and at a particular location), each of which could be related to the availability of prey (fish) in the early spring (April, May) during egg laying and incubation. Consistency of nesting success was associated with the presence of tidal flats at one study site. Nest use, but not nesting success, was related to nesting success the previous year. Multiple regression showed that fewer nests per kilometre were successful in years with a high frequency of spring rains.

Common Loon (Gavia immer)

1997 ◽  
Author(s):  
Judith W. McIntyre ◽  
Jack F. Barr
Keyword(s):  
Gavia Immer ◽  
Common Loon

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.

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