Diving schedules of Common Loons in varying environments

2002 ◽  
Vol 80 (9) ◽  
pp. 1643-1648 ◽  
Author(s):  
Joseph J Nocera ◽  
Neil M Burgess
Keyword(s):  
Environmental Variation ◽  
Dive Duration ◽  
Diving Behaviour ◽  
Fish Abundance ◽  
Gavia Immer ◽  
Lake Chemistry ◽  
Common Loons ◽  
The Common ◽  
Varying Environments ◽  
External Stimuli

Many species of diving birds adjust their foraging behaviour in response to variation in their environment. The Common Loon (Gavia immer) is a visually oriented predator sensitive to environmental variation, yet little is known about the flexibility of its diving behaviour. We tested the hypothesis that loons adjust their diving schedules by increasing or decreasing the dive duration during foraging bouts to accommodate environmental variation during the breeding season. The dive duration and dive-pause components of the loon dive cycle did not vary among lakes with different lake chemistry, lake morphometry, mercury levels in their blood, or fish abundance. We observed some variation among loons in different stages of breeding in mean dive-pause intervals. The dive-pause component of the diving cycle of Common Loons does not seem to be related to the amount of time spent underwater. To our knowledge, this is the first report of such a nonlinear relationship in diving birds. We propose that loons vary the components of their diving behaviour independently and seem to alter their diving time budgets regardless of the external stimuli we addressed. This unresponsive diving schedule may make loons susceptible to catastrophic changes in prey densities within their foraging areas, as they are obliged to forage on one, or very few, lakes. Conversely, loons may only forage in lakes with fish abundance above a certain minimum threshold and preferentially avoid lakes with reduced prey abundance.

scholarly journals Nocturnal Behavior of the Common Loon, Gavia immer

2008 ◽  
Vol 122 (1) ◽  
pp. 70 ◽  
Author(s):  
James D. Paruk
Keyword(s):  
Night Vision ◽  
Energy Budgets ◽  
Single Pair ◽  
Gavia Immer ◽  
Complete Understanding ◽  
Large Lakes ◽  
Common Loons ◽  
Nocturnal Behavior ◽  
Daily Energy ◽  
The Common

Very little is known about nocturnal activity of Common Loons (Gavia immer). Knowledge of both diurnal and nocturnal behavior is needed to gain a complete understanding of their ecology. I used night vision light intensifiers to observe nocturnal behaviors of Common Loons. Results were consistent with the hypothesis that, as visual predators, loons would not forage at night and also that they would spend the majority of their time resting (92%). Loons, however, were just as active locomoting (patrolling) during the night as they were during the day. This suggests daily energy budgets need to be reexamined to incorporate this overlooked aspect of loon behavior. Lastly, loons on large lakes with multiple loon territories spent more time locomoting than loons on lakes that had just a single pair.

AN OUTBREAK OF TYPE E BOTULISM AMONG COMMON LOONS (GAVIA IMMER) IN MICHIGAN'S UPPER PENINSULA

1988 ◽  
Vol 24 (3) ◽  
pp. 471-476 ◽  
Author(s):  
Christopher J. Brand ◽  
Stephen M. Schmitt ◽  
Ruth M. Duncan ◽  
Thomas M. Cooley
Keyword(s):  
Gavia Immer ◽  
Upper Peninsula ◽  
Common Loons

Loon abundance and behaviour over four decades at a remote ecological reserve on Haida Gwaii, British Columbia, Canada

2021 ◽  
Vol 135 (1) ◽  
pp. 28-38
Author(s):  
Thomas Reimchen ◽  
Sheila Douglas
Keyword(s):  
British Columbia ◽  
Gasterosteus Aculeatus ◽  
Evolutionary Ecology ◽  
Inverse Correlation ◽  
Gavia Immer ◽  
Haida Gwaii ◽  
Average Wind Speed ◽  
The North ◽  
Common Loons ◽  
Ecological Reserve

Early studies (1976–1982) of the Drizzle Lake Ecological Reserve on Haida Gwaii, British Columbia focussed on the endemic Giant Threespine Stickleback (Gasterosteus aculeatus) and their predators. These surveys showed daily visits to the small lake (110 ha) by up to 59 adult non-breeding Common Loon (Gavia immer), an important stickleback predator and up to 19 breeding and non-breeding adult Red-throated Loon (Gavia stellata), which leave daily to forage in nearby marine waters. We continued loon surveys for 17 additional years (1983–1989, 2011–2020) and found that aggregations of non-breeding Common Loons occurred annually on the lake during July with maximum daily numbers of 78–83 individuals in 1987, 2018, and 2020 and a large increase from 2011 to 2020. We did not detect any relationship of these differences with the Pacific Decadal Oscillation but a significant inverse correlation with average wind speed. Average yearly numbers of Red-throated Loons declined by 50% from 1976 to 1989 and have remained low, with lowest numbers (<2) occurring in 2017. Two Red-throated Loon nesting territories on the lake were occupied from 1976 to 1995, with chicks occurring in 24 of 36 nests, but no successful nesting was observed on the lake over the last decade. The relative decline of Red-throated Loon in this reserve is similar to that reported in Arctic and Subarctic surveys of the species in the north Pacific and northern Europe. We discuss the implications for the evolutionary ecology of the sticklebacks and the conservation of the ecological reserve.

The breeding success of common loons (Gavia immer) in relation to alkalinity and other lake characteristics in Ontario

1988 ◽  
Vol 66 (3) ◽  
pp. 746-752 ◽  
Author(s):  
Robert Alvo ◽  
David J. T. Hussell ◽  
Michael Berrill
Keyword(s):  
Breeding Success ◽  
Benthic Algae ◽  
Gavia Immer ◽  
Acidic Lake ◽  
Acidic Lakes ◽  
Common Loons ◽  
Breeding Attempt ◽  
High Alkalinity ◽  
Highly Correlated ◽  
High Level

We examined the breeding success of common loons (Gavia immer) and made observations of loons feeding their young on small lakes (5.3–75 ha) with different alkalinities (−73 to 1804 μequiv./L) near Sudbury, Ontario. Alkalinity, pH, and conductivity were highly correlated with each other. There was a significant positive relationship between successful breeding and alkalinity on 68 lakes surveyed in 1982. Discriminant analysis showed that alkalinity, area, and colour of the lake contributed significantly to discrimination among lakes with successful, unsuccessful, and no breeding attempts. Lack of a breeding attempt tended to be associated with small, brown, low-alkalinity lakes, and successful breeding with large, clear, high-alkalinity lakes. For lakes with breeding attempts in 1982–1984, alkalinity (all years), depth (1983), and area (1984) provided significant discrimination between unsuccessful lakes and those on which young were raised. Unsuccessful breeding resulted primarily from brood mortalities on acidic lakes. Adult loons were more successful at securing fish on high-alkalinity lakes than on low-alkalinity lakes, and this may reflect differences in fish densities. A pair of loons attempting to raise a chick on a fishless, acidic lake fed the chick benthic algae and possibly benthic invertebrates, but flew to other lakes to feed themselves. We suggest that the high level of brood mortalities on acidic lakes resulted from a shortage of suitable food for the young.

Juvenile survival in common loons Gavia immer: effects of natal lake size and pH

2012 ◽  
Vol 43 (3) ◽  
pp. 280-288 ◽  
Author(s):  
Walter H. Piper ◽  
Jason S. Grear ◽  
Michael W. Meyer
Keyword(s):  
Juvenile Survival ◽  
Gavia Immer ◽  
Common Loons ◽  
Lake Size

SPECIAL REVIEWS

PEDIATRICS ◽  
1951 ◽  
Vol 7 (2) ◽  
pp. 269-293
Author(s):  
CHARLES C. CHAPPLE
Keyword(s):  
The Body ◽  
Caloric Content ◽  
Maturation Factor ◽  
Drug Actions ◽  
The Common ◽  
Cellular Permeability ◽  
The One ◽  
External Stimuli ◽  
The Brain

A study has been made of the known phenomena which affect the biologic organism. Certain correlations have been found and other correlations are logically inferred. The common grounds of anatomic structures, the anatomic responses to endocrine stimuli, the interrelationships and interdependencies of the endocrines and external stimuli have been followed and have been related to cellular permeability and hyaluronic acid. Cellular phases, including the rhythmic alternations in physiologic functions, have been delineated and their importance stressed. Further, the probability is advanced that this rhythmicity originates physiologically in the brain but that the brain itself is capable of receiving transmissions from within and without the body, and disseminating them, again rhythmically, in normal or altered amplitude and frequency. Further experimental evidence of these correlations and their practical extrapolations into drug actions and the therapy of infections and metabolic disease will be reported and will include clinical, animal and in vitro studies. At present, the following conclusions seem justified: 1. No component of the body is capable of independent action. 2. Action in any component is reflected, according to its magnitude and directness of application, upon all the body. 3. All such actions are mediated by the brain. 4. There is a dynamic, rhythmic cyclicity in physiologic action which can be altered in amplitude and frequency. 5. These rhythms are alternations of cellular tenseness and relaxation. 6. The concomitants of the tense phase are compactness, impermeability, electric conductivity and contraction of all cells, and these characteristics might be described collectively as the factors operative in maturing the cell. The concomitants of the relaxed phase are laxness, permeability, electric resistance and expansion of all cells and are factors of growth. 7. The phase of tenseness is accompanied by an increase in certain hormonal activities and that of relaxation by an increase in others. 8. The hormones may be causes of the phase or the results of it. 9. Infectious disease cannot act as an extraneous agent capable of bringing its own engine into such a highly integrated mechanism but must act on the body through its ability to affect one of the body's mechanisms. 10. Drugs must act through the same channels available to disease. 11. Foods may contain, in addition to their caloric content, components capable of stimulating either the phase of cellular expansion or cellular compaction, particularly foods from the reproductive systems of plants or animals (milk, eggs, cereal, for example). 12. Vitamins each stimulate one phase and should be evaluated in terms of positive actions. 13. Inherent growth and maturation factors are not of fixed capacity in an individual but beyond certain limits must be supplied him or applied to him constantly. 14. The hormone most manifest in the tense phase is estrogen and so may be considered the maturation factor, and the one most manifest in the phase of relaxation or cell division is progesterone, which may be considered the growth factor.

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