Clutch Size, Breeding Success and Brood Size Experiments in Tengmalm's Owl Aegolius funereus: A Test of Hypotheses

1987 ◽  
Vol 18 (4) ◽  
pp. 277 ◽  
Author(s):  
Erkki Korpimaki
Keyword(s):  
Clutch Size ◽  
Breeding Success ◽  
Brood Size ◽  
Aegolius Funereus ◽  
Test Of Hypotheses ◽  
Tengmalm's Owl

Effects of cyclic food supply on breeding performance in Tengmalm's owl (Aegolius funereus)

1990 ◽  
Vol 68 (3) ◽  
pp. 522-530 ◽  
Author(s):  
Birger Hörnfeldt ◽  
Bengt-Göran Carlsson ◽  
Ola Löfgren ◽  
Ulf Eklund
Keyword(s):  
Clutch Size ◽  
Relative Abundance ◽  
Food Supply ◽  
Snow Depth ◽  
Nest Survival ◽  
Clethrionomys Glareolus ◽  
Laying Date ◽  
Aegolius Funereus ◽  
Bank Voles ◽  
Tengmalm's Owl

Cyclic populations of bank voles (Clethrionomys glareolus), grey-sided voles (Clethrionomys rufocanus), and field voles (Microtus agrestis) made up > 90% of the diet of Tengmalm's owl (Aegolius funereus) in northern Sweden during the breeding seasons of 1980–1986. These voles also made up > 90% of snap-trapped small mammals in the study area. Comparisons of the species composition in the diet during laying with that of animals trapped indicated that bank voles were usually taken approximately in proportion to their relative abundance, whereas field voles were frequently taken more and grey-sided voles less than expected from their relative abundance. However, bank voles predominated in the diet during laying early in the season (snow depth > 40 cm). Later in the season (snow depth ≤ 40 cm) the porportion of field voles and grey-sided voles increased during laying, suggesting increased availability of these species as the snow melted. Breeding density (percentage of nest boxes with ≥ 1 egg) showed a positive correlation whereas laying date showed a negative correlation with food supply in autumn. In contrast, clutch size, number of fledglings per successful nest, and an index of the annual production of fledglings showed positive correlations with food supply in spring. Clutch size declined with season but at different levels in different years, and laying date per se only explained 11% of clutch size variation among years. In contrast, the "year effect" (related to food supply) explained 29% of the variation in clutch size. Clutches were even larger at later laying dates (when, however, the food supply was better) in 1984 than in 1985. Nest survival and survival per egg (until fledging) in successful nests varied over the years, but did not covary with the cyclic food supply. However, the lowest nest survival was found in a year when voles declined dramatically over winter. Egg size did not show any variation among years.

ECOLOGY AND BREEDING BIOLOGY OF CHESTNUT-TAILED STARLING, STURNUS MALABARICUS (GMELIN 1789)

1970 ◽  
Vol 11 (1) ◽  
Author(s):  
M. F. Jaman ◽  
N. Sahreen
Keyword(s):  
Key Words ◽  
Incubation Period ◽  
Clutch Size ◽  
Breeding Season ◽  
Breeding Success ◽  
Brood Size ◽  
Nest Building ◽  
Breeding Biology ◽  
Egg Incubation ◽  
The Mean

Studies on the ecology and breeding biology of Chestnut-tailed Starling, Sturnus malabaricus (Gmelin) were carried out from June 1997 to July 1998 in Dhaka and Nilphamari districts. This bird mainly found in parties and small flocks on the upper canopy and leaf of the trees to feed on insects. Breeding season of this bird started from the early February and ended to last July. A total of 30 nests were studied those were found in 5 species of trees and in the ventilation of buildings in five study areas. The peak nesting period was in March. Both sexes took part in nest building, egg incubation, brooding and feeding of nestlings. The mean clutch size was 3 ± 0.63 eggs. Out of 30 eggs belonged to 10 nests, 20 (66.67%) were hatched and the rest 10 (33.33%) were lost and infertile. The mean incubation period was 17 ± 1.3 days. Brood size varied from 1-3 nestlings. Out of 20 nestlings hatched, 10 (50%) were fledged successfully. The breeding success was 33.33% in relation to the number of eggs laid and 50% in relation to the nestlings hatched. The fledging period varied from 19 to 21 days. Key words: Ecology, breeding biology, Chestnut-tailed Starling, Sturnus malabaricus. Ecoprint Vol.11(1) 2004.

Bigyny in Tengmalm's Owl Aegolius funereus: Effect of Mating Strategy on Breeding Success

1987 ◽  
Vol 18 (4) ◽  
pp. 237 ◽  
Author(s):  
B.-G. Carlsson ◽  
B. Hornfeldt ◽  
O. Lofgren
Keyword(s):  
Breeding Success ◽  
Mating Strategy ◽  
Aegolius Funereus ◽  
Tengmalm's Owl

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

Trigyny in Tengmalm's Owl Aegolius funereus Induced by Supplementary Feeding?

1989 ◽  
Vol 20 (2) ◽  
pp. 155 ◽  
Author(s):  
Bengt-Goran Carlsson ◽  
Birger Hornfeldt
Keyword(s):  
Supplementary Feeding ◽  
Aegolius Funereus ◽  
Tengmalm's Owl

Physiological and biochemical correlates of brood size and energy expenditure in tree swallows

2001 ◽  
Vol 204 (8) ◽  
pp. 1491-1501 ◽  
Author(s):  
G.P. Burness ◽  
R.C. Ydenberg ◽  
P.W. Hochachka
Keyword(s):  
Clutch Size ◽  
Brood Size ◽  
Mass Gain ◽  
Pectoral Muscle ◽  
Population Variation ◽  
Tree Swallows ◽  
Internal Organs ◽  
Doubly Labelled Water ◽  
Energy Expenditures ◽  
Physiological And Biochemical

Intra-population variation in many fitness-related traits (e.g. clutch size) is often attributed to variation in individual parental quality. One possible component of quality is the level at which each individual can expend energy while provisioning dependent young. We used breeding tree swallows (Tachycineta bicolor) to test whether adults with large, natural-sized broods and/or nestlings in good nutritional condition had relatively high daily energy expenditures (DEEs). Adults with high DEEs were predicted to have large internal organs and high metabolic capacities. We first measured the growth rate of nestlings in natural broods of five, six and seven over a 4-day period and then measured parental DEE using doubly labelled water. Adults were then dissected for analyses of body composition and to determine maximum enzyme activities in the pectoral muscle. Although the total mass gain of large broods was greater than that of small broods, parental DEE was independent of brood size. We hypothesize that adults matched their clutch size (and consequently, brood size) to their individual foraging efficiencies. When statistically controlling for the effects of brood size, in one of two years there was a positive correlation between DEE and brood mass. This suggests that among individuals rearing the same-sized broods there were reproductive benefits of a relatively high DEE. There was no correlation between either brood size or DEE and the mass of any internal organ or the metabolic capacity of the pectoral muscle.

scholarly journals Breeding biology of coppersmith barbet, Megalaima haemacephala (Müller, 1776)

2013 ◽  
Vol 31 ◽  
pp. 31-34
Author(s):  
Noor Jahan Sarker ◽  
M Firoj Jaman ◽  
Shariar Mustafa ◽  
Md Saidur Rahman
Keyword(s):  
Incubation Period ◽  
Breeding Season ◽  
Breeding Success ◽  
Brood Size ◽  
Botanical Garden ◽  
Egg Laying ◽  
Breeding Biology ◽  
Average Weight ◽  
Average Height ◽  
Average Depth

Breeding biology of the Coppersmith barbet, Megalaima haemacephala (Müller, 1776) was carried out between February, 2006 and January, 2007 at Sharawardy Uddyan, Ramna Park, Curzon Hall and National Botanical Garden. The breeding season started from December and ended in June. In total 20 nests were observed, of which 10 nests were studied in details in four study areas. The coppersmith barbet mostly preferred to make holes on the branches of koroi (Albizzia procera) for nesting. Egg laying started on 15th February in the study areas. Average height of nests from the ground was 9.7m and average depth and diameter of the holes was 29.20cm and 4.46cm respectively. New holes were constructed yearly or the old one was reused. Both the sexes took part in incubation of eggs, brooding and feeding to the nestlings. A total of 30 eggs were laid in 10 nests. Clutch size varied from 2 – 4 eggs (average: 3 eggs). Among them, 20 (66.67%) eggs were hatched and the rest 10 (33.33%) were unhatched and lost. Average incubation period was 14 days. The male and the female incubated the eggs for an average of 27.44 minutes/ hours and 32.56 minutes/ hours, respectively. Average number of nestlings (brood size) per nest was 2. Out of 20 nestlings, 16 left their nests successively. The breeding success was 53.33% in relation to the number of eggs laid and 80% in relation to nestlings hatched. The average weight of eggs and nestlings was 3.59g and 9.33g, respectively. The main causes of loss of the eggs and nestlings were human interference, predation and ectoparasitic infections. Insects and fruits were fed to the nestlings by their parents.DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15397Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 31-34 

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