Redhead (Aythya americana)

2002 ◽  
Author(s):  
Marc C. Woodin ◽  
Thomas C. Michot
Keyword(s):  
Aythya Americana

Aythya Americana (Redhead) 2n = 80

1973 ◽  
pp. 197-199
Author(s):  
Maria Luiza Beçak ◽  
Willy Beçak ◽  
Franklin L. Roberts ◽  
Robert N. Shoffner ◽  
E. Peter Volpe
Keyword(s):  
Aythya Americana

scholarly journals Additional Data and Perspectives on Interspecific Aggression in the Common Loon, Gavia immer

2011 ◽  
Vol 125 (1) ◽  
pp. 61
Author(s):  
Martin L. Morton ◽  
Maria E. Pereyra
Keyword(s):  
Additional Data ◽  
Gavia Immer ◽  
Common Loon ◽  
Interspecific Aggression ◽  
Aythya Americana ◽  
The Common

We witnessed the killing of a female Redhead (Aythya Americana) by a male Common Loon (Gavia immer). The wound was delivered into the abdomen from below, and death occurred because of a torn, hemorrhaging liver. This same Common Loon also threatened a female Ring-necked Duck (Aythya collaris) with ducklings. We hypothesize that interspecific aggression by loons might be energetically costly but is sometimes adaptive because it deters predators.

scholarly journals The contribution of nasal receptors to the cardiac response to diving in restrained and unrestrained redhead ducks (Aythya americana)

1986 ◽  
Vol 121 (1) ◽  
pp. 227-238 ◽  
Author(s):  
R. A. Furilla ◽  
D. R. Jones
Keyword(s):  
Heart Rate ◽  
Local Anaesthesia ◽  
Cardiac Response ◽  
Dabbling Ducks ◽  
Diving Ducks ◽  
Cardiac Responses ◽  
Aythya Americana ◽  
Dabbling Duck ◽  
Redhead Ducks ◽  
A Minor

In restrained redhead ducks, forced submergence caused heart rate to fall from 100 +/− 3 beats min-1 (mean +/− S.E.M., N = 12) to a stable underwater rate of 35 +/− 4 beats min-1 (N = 12) within 5 s after submergence. Bradycardia was unaffected by breathing oxygen before a dive, but was virtually eliminated by local anaesthesia of the narial region. In contrast, in a dabbling duck (Anas platyrhynchos) bradycardia in short dives was eliminated by breathing oxygen before a dive. In unrestrained diving, on a man-made pond, heart rate in redheads diving voluntarily (y) was related to pre-dive heart rate (x) by the equation y = 76 + 0.29 +/− 0.05x +/− 17 (r2 = 0.71). Chasing, to induce submergence, had variable effects on this relationship. Local anaesthesia of the narial region inhibited voluntary diving but heart rates in chase-induced dives after nasal blockade were significantly higher, by 10–30%, than those obtained from untreated ducks in chase-induced dives. Breathing oxygen before voluntary dives had no apparent effect on heart rate after 2–5 s submergence. Voluntary head submersion by dabbling ducks caused no change in heart rate. We conclude that nasal receptors make only a minor contribution to cardiac responses in unrestrained dives, compared with forced dives, in diving ducks. Furthermore, these results show that little can be learned about cardiac responses in free diving ducks from studies of forced dives in dabblers or divers.

Migration and Mortality of Hand-Reared Redheads (Aythya americana)

1959 ◽  
Vol 23 (4) ◽  
pp. 427 ◽  
Author(s):  
Milton W. Weller ◽  
Peter Ward
Keyword(s):  
Aythya Americana

scholarly journals Habituation of the cardiac response to involuntary diving in diving and dabbling ducks

1987 ◽  
Vol 131 (1) ◽  
pp. 403-415 ◽  
Author(s):  
G. R. Gabbott ◽  
D. R. Jones
Keyword(s):  
Blood Gases ◽  
Cardiac Response ◽  
Dabbling Ducks ◽  
Ventilatory Responses ◽  
Arterial Blood ◽  
Aythya Americana ◽  
Habituation Training ◽  
Before And After ◽  
The Central Nervous System ◽  
Low Levels

1. Bradycardia in response to forced submergence was habituated in dabbling (Anas platyrhynchos, Linnaeus) and diving (Aythya americana, Eyton) ducks by repetitively submerging the animals, each day for several days, for periods of 40 and 20 s, respectively. The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Diving bradycardia is driven by chemoreceptors in the dabbler and caused by stimulation of narial receptors in the diver. 2. Mean arterial blood pressure in dives was unchanged from pre-dive levels in both naive and trained dabbling ducks. PaO2, PaCO2 and pHa at the end of a dive were similar before and after habituation training. 3. Bradycardia occurred in dives by habituated dabbling ducks if the animal breathed 15% O2 before submergence. The ventilatory responses to breathing high and low levels of oxygen were unaffected by habituation training. 4. The changes in blood gases during dives by naive and habituated dabbling ducks were the same: therefore, in the absence of a demonstrated decrement in receptor chemosensitivity or efferent potency, the locus of habituation must reside in the central nervous system.

scholarly journals Blood flow distribution in submerged and surface-swimming ducks

1992 ◽  
Vol 166 (1) ◽  
pp. 285-296
Author(s):  
R. Stephenson ◽  
D. R. Jones
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Water Surface ◽  
Imaging Technique ◽  
Flow Distribution ◽  
Tissue Blood Flow ◽  
Blood Flow Distribution ◽  
Radiological Imaging ◽  
Aythya Americana

Observations that the response of the avian heart rate to submergence varies under different circumstances have led to speculation about variability of blood flow distribution during voluntary dives. We used a radiological imaging technique to examine the patterns of circulating blood flow in captive redhead ducks (Aythya americana) during rest, swimming, escape dives, forced dives and trapped escape dives and have shown that blood flow distribution in escape dives was the same as that in ducks swimming at the water surface. The response during trapped escape dives, however, was highly variable. Blood pressure was unchanged from the resting value during all activities. Predictions made about blood flow distribution during unrestrained dives on the basis of heart rate and other indirect data were confirmed in this study. However, the trapped escape dive responses indicated that heart rate alone is not always a reliable indicator of tissue blood flow in exercising ducks.

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