Fertility, egg weight loss, hatchability, and fledging success in replacement clutches of captive American Kestrels

1982 ◽  
Vol 60 (1) ◽  
pp. 80-88 ◽  
Author(s):  
David M. Bird ◽  
Paul C. Laguë
Keyword(s):  
Weight Loss ◽  
Falco Sparverius ◽  
Egg Weight ◽  
Fledging Success ◽  
American Kestrels ◽  
Artificial Incubation

From 1974 to 1977, 78 pairs of captive American Kestrels (Falco sparverius) were induced to lay replacement clutches by removal and artificial incubation of their first clutches. No significant differences existed between first and replacement clutches for fertility, hatchability, and fledging success. Hatchability, as well as fledging success of young, did not differ significantly between artificially and naturally incubated eggs. Both fertility and hatchability declined with eggs laid later in the season.

Reproductive performance of American Kestrels laying replacement clutches

1985 ◽  
Vol 63 (11) ◽  
pp. 2590-2593 ◽  
Author(s):  
Reed Bowman ◽  
David M. Bird
Keyword(s):  
Reproductive Success ◽  
Reproductive Performance ◽  
Falco Sparverius ◽  
Nestling Growth ◽  
Fledging Success ◽  
American Kestrels ◽  
First Clutch ◽  
Second Clutch

Egg dimensions, nestling growth, and reproductive success were compared between first and second clutch nests of American Kestrels (Falco sparverius) to determine the influence of renesting on fledging success. Eggs were removed from 11 nests during 1982–1983. Eight nests served as controls. Most pairs (81.8%) renested on their original territory. We found no significant differences in egg dimensions, fertility, or hatchability between the two groups. Second clutch males (n = 6 clutches) were smaller at hatching than males from first clutches (n = 8 clutches). By day 24 these males (n = 5 clutches) were heavier, with significantly longer manus and antebrachia than first clutch males (n = 3 clutches). However, five of eight first clutch nests fledged all males before day 24. Males remaining in first clutch nests beyond day 24 were lighter with significantly smaller antebrachia by day 18 than males fledging before day 24. This may have biased our comparisons between first and second clutch males. No significant differences in growth were found between female groups. First-clutch progeny fledged significantly younger than second-clutch birds. Males fledged earlier than females in first clutches, but the sexes fledged simultaneously in second clutches.

Nestling growth and fledging success in manipulated American kestrel broods

1992 ◽  
Vol 70 (12) ◽  
pp. 2421-2425 ◽  
Author(s):  
Nicholas W. Gard ◽  
David M. Bird
Keyword(s):  
Clutch Size ◽  
Growth Rates ◽  
Brood Size ◽  
Wild Birds ◽  
Falco Sparverius ◽  
Nestling Growth ◽  
American Kestrel ◽  
Fledging Success ◽  
American Kestrels ◽  
Parental Ability

To study factors regulating clutch size in American Kestrels (Falco sparverius), brood manipulation experiments were performed on captive and wild birds in southwestern Quebec during 1986 and 1987. The largest normally occurring brood size was 5 young. Manipulations enlarged or decreased broods to 7 or 2 young, respectively. Significantly more young fledged from wild control and enlarged broods in 1987 than from comparable groups in 1986. The average number of young fledging from enlarged wild broods in 1987 was slightly higher than for control broods, but fledging weight was significantly depressed in enlarged broods. Growth rates and tarsal and antebrachial length at fledging were not affected by brood size, but development of primary feathers was slower in enlarged wild broods. Parental ability to adequately feed all young appears to be the major factor limiting brood size in American Kestrels.

Influence of forced renesting, seasonal date of laying, and female characteristics on clutch size and egg traits in captive American Kestrels

1982 ◽  
Vol 60 (1) ◽  
pp. 71-79 ◽  
Author(s):  
David M. Bird ◽  
Paul C. Laguë
Keyword(s):  
Clutch Size ◽  
Eggshell Thickness ◽  
Falco Sparverius ◽  
Egg Weight ◽  
American Kestrels ◽  
First Clutch ◽  
Egg Traits

Of 78 nesting attempts by captive American Kestrels (Falco sparverius) between 1974 and 1977, 95% successfully renested after removal of the first clutch. Replacement clutches had fewer eggs, longer eggs, and eggs with thicker shells than first clutches. Clutch size, egg length, eggshell thickness, and fresh egg weight declined seasonally. Renesting intervals were shorter in older, experienced layers and clutch size increased by 0.20 eggs with each additional year of age.

Reproductive changes in American kestrels (Falco sparverius) in relation to exposure to technical hexabromocyclododecane flame retardant

2011 ◽  
Vol 30 (11) ◽  
pp. 2570-2575 ◽  
Author(s):  
Kim J. Fernie ◽  
Sarah C. Marteinson ◽  
David M. Bird ◽  
Ian J. Ritchie ◽  
Robert J. Letcher
Keyword(s):  
Flame Retardant ◽  
Falco Sparverius ◽  
American Kestrels

The influence of Trichinella pseudospiralis infection on the behaviour of captive, nonbreeding American kestrels (Falco sparverius)

1988 ◽  
Vol 66 (7) ◽  
pp. 1685-1692 ◽  
Author(s):  
Michèle D. Saumier ◽  
Manfred E. Rau ◽  
David M. Bird
Keyword(s):  
Falco Sparverius ◽  
Competitive Fitness ◽  
American Kestrel ◽  
Behavioural Changes ◽  
Trichinella Pseudospiralis ◽  
Behavioural Effects ◽  
American Kestrels ◽  
Muscle Larvae ◽  
Adult Phase ◽  
Muscle Groups

Trichinella pseudospiralis infections induced mild behavioural changes in the American kestrel host (Falco sparverius) within the first 5 days postinoculation, a period that corresponds to the adult phase of the infection. However, more severe effects on mobility were precipitated as the larvae migrated and became established in the musculature. The debilitation persisted for at least 5 weeks postinoculation and involved a reduction in exercising, flying, elevated perching, and preening, and was accompanied by an increase in the frequency of walking and floor perching. Such behavioural effects, attributable to the presence of muscle larvae, may reduce the competitive fitness of infected individuals. The muscle larvae were randomly distributed among various muscle groups.

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