Photoperiodic induction of multiple breeding seasons in captive American kestrels

1980 ◽  
Vol 58 (6) ◽  
pp. 1022-1026 ◽  
Author(s):  
David M. Bird ◽  
P. Gregory Weil ◽  
Paul C. Laguë
Keyword(s):  
Light Intensity ◽  
Winter Season ◽  
Egg Laying ◽  
Breeding Period ◽  
Photoperiodic Induction ◽  
Negative Effects ◽  
Ambient Temperatures ◽  
American Kestrels ◽  
Artificial Photoperiod ◽  
Breeding Seasons

Six out of 10 mated pairs of captive American kestrels (Falco sparverius) were induced by artificial photoperiod to undergo a successful out-of-season breeding period between two consecutive successful spring breeding periods. Light intensity had significant (r = −0.88, p < 0.05) negative effects on onset of egg laying. Eighteen of the 27 eggs produced were laid at ambient temperatures below freezing. Fertility (85.2%), hatchability of fertile eggs (47.6%), and fledging success (100%) in the winter season were all highly comparable with the two spring breeding seasons.

NESTING AND BREEDING ECOLOGY OF MARINE TURTLE IN ST. MARTIN'S CORAL ISLAND, BANGLADESH

1970 ◽  
Vol 11 (1) ◽  
Author(s):  
M.L. Hossain ◽  
M.F. Jaman ◽  
S.U. Sarker ◽  
S.U. Mahmood
Keyword(s):  
Winter Season ◽  
Chelonia Mydas ◽  
Egg Laying ◽  
Marine Turtle ◽  
Breeding Period ◽  
Breeding Ecology ◽  
Olive Ridley ◽  
On This Island ◽  
The Mean ◽  
Monitor Lizards

Observations on nesting and breeding ecology of three species of marine turtle were made in St. Martin's Island, Bangladesh. The egg laying period was found to be in winter season between October and March. The peak breeding period was in December and January. The mean diameter of the nests of Olive ridley turtle, Lepidochelys olivacea was 27.42 ± 5.2 cm. Green turtle, Chelonia mydas 25.67 ± 1.53 cm and Loggerheaded turtle, Caretta caretta 27.65 ± 1.52 cm. The mean depth of nest of L. olivacea was 49.17 ± 5.61 cm, C. mydas 51 ± 2.65 cm and C. caretta 54.33 ± 1.53 cm. Mean clutch size of L. olivacea was 115.6 ± 16.7 eggs, C. mydas 112.15 ± 11.52 eggs and C. caretta 122 ± 18.62 eggs. The mean weight of eggs of L. olivacea was 31.63 ± 1.83. C. mydas 32.71 ± 1.26 and C, caretta 32.45 ± 3.75, Mean incubation period of L. olivacea was 63.9 ± 3.5 days, C. mydas 61.85 ± 2.57 days and C. caretta 61.5 ± 1.29 days. The mean hatching success of L. olivacea was 81.14%, C. mydas was 80.11%, and C. caretta 84.43%. The mean weight of hatchlings of L. olivacea was 14.7 ± 0.58g, C. mydas 15.4 ± 0.78 g and C. caretta 16.20 ± 0.3 5 g. Loss of nesting ground by the local people and visitors and poaching of eggs and injured of mother turtles by the dogs was the main problems for breeding of turtles on this island. Construction of embankments for control of erosion, destruction of nests by indigenous dogs and monitor lizards should be protected. Immediate conservation measures are warranted to save the breeding of turtles on this island. Key words: Nesting, breeding, ecology, marine turtles, conservation. Ecoprint Vo.11(1) 2004.

scholarly journals Observations on breeding behaviour of a pair of endangered Egyptian Vultures Neophron percnopterus (Linnaeus, 1758) over three breeding seasons in the plains of Punjab, India

2020 ◽  
Vol 12 (9) ◽  
pp. 16013-16020
Author(s):  
Charn Kumar ◽  
Amritpal Singh Kaleka ◽  
Sandeep Kaur Thind
Keyword(s):  
Incubation Period ◽  
Egg Laying ◽  
Breeding Period ◽  
Space Observatory ◽  
The Third ◽  
Breeding Behaviour ◽  
Nest Activity ◽  
Nesting Site ◽  
Breeding Seasons ◽  
Cctv Camera

The present study has been conducted to document information on breeding behaviour of Egyptian Vultures Neophrons percnopterus from Punjab.  This study is based on 688 hours of video records documenting breeding behaviour of a pair of endangered Egyptian Vultures Neophrons percnopterus occupying the same nesting site over three consecutive breeding seasons from 2015 to 2017. The site is located in the hollow of a ventilation window of the Space Observatory in Punjabi University, Patiala, Punjab. During the third breeding period (February to August 2017), the nest activity has been extensively video-recorded in egg laying and incubation period, and chick rearing period using a Dome CCTV Camera. Both parents participated in nest building, and of the total recorded incubation time of 339.39h over 23 days the nest was attended for 199.35 and 139.46h by the female and male respectively, and unattended for 0.58h. The incubation period was 42 to 43 days, and the egg laying/hatching intervals between eggs/chicks was five days. A total of six young ones hatched and fledged from three broods of two eggs each. All chicks survived to fledging and no mortality or siblicide of younger chick occurred due to aggression/starvation by elder chick. The high fledging success rate indicates a healthy habitat and food source in the nesting area. 

scholarly journals Environmental determinants of haemosporidian parasite prevalence in a declining population of Tree swallows

Parasitology ◽  
2017 ◽  
Vol 145 (7) ◽  
pp. 961-970 ◽  
Author(s):  
Audrey Turcotte ◽  
Marc Bélisle ◽  
Fanie Pelletier ◽  
Dany Garant
Keyword(s):  
Forest Cover ◽  
Agricultural Landscape ◽  
Parasite Prevalence ◽  
Landscape Composition ◽  
Breeding Period ◽  
Tree Swallows ◽  
Environmental Determinants ◽  
Negative Effects ◽  
Haemosporidian Parasite ◽  
Haemosporidian Parasites

AbstractThe prevalence of vector-borne parasites such as haemosporidian species is influenced by several environmental factors. While the negative effects of parasitism on hosts are well documented, these can also be amplified by interactions with environmental stressors, many of which are anthropogenic. Yet, we know little about the possible effects of anthropogenic perturbations on parasite prevalence. The goals of this study were to assess the prevalence and environmental determinants of haemosporidian parasites in a declining population of Tree swallows (Tachycineta bicolor) living in an agricultural landscape in southern Québec, Canada. Overall, a low prevalence and a moderate lineage diversity were identified in both adults and nestlings, confirming that transmission can occur during the breeding period. Anthropic areas, extensive cultures (hayfields and pastures) and forest cover within 500 km of nest boxes, as well as daily temperature fluctuations, were all related to infection by haemosporidian parasites. These findings suggest that anthropogenic alterations of landscape composition can modulate the prevalence of haemosporidian parasites in Tree swallows. Our results represent a baseline for future comparative studies assessing haemosporidian parasite prevalence in human-modified landscapes.

scholarly journals Polarization-based brightness discrimination in the foraging butterfly, Papilio xuthus

2011 ◽  
Vol 366 (1565) ◽  
pp. 688-696 ◽  
Author(s):  
Michiyo Kinoshita ◽  
Kei Yamazato ◽  
Kentaro Arikawa
Keyword(s):  
Light Intensity ◽  
Animal Species ◽  
Brightness Discrimination ◽  
Egg Laying ◽  
Polarization Vision ◽  
Discrimination Test ◽  
Spectral Content ◽  
Papilio Xuthus ◽  
Choice Tests ◽  
Vector Orientation

The human eye is insensitive to the angular direction of the light e-vector, but several animal species have the ability to discriminate differently polarized lights. How the polarization is detected is often unclear, however. Egg-laying Papilio butterflies have been shown to see false colours when presented with differently polarized lights. Here we asked whether this also holds in foraging butterflies. After training individuals to feed on nectar in front of an unpolarized spectral light, we carried out three dual-choice tests, where the discrimination of (i) the spectral content, (ii) the light intensity, and (iii) the e-vector orientation were investigated. In the first test, the butterflies selected the trained spectrum irrespective of its intensity, and in the second test they chose the light with the higher intensity. The result of the e-vector discrimination test was very similar to that of the second test, suggesting that foraging butterflies discriminate differently polarized lights as differing in brightness rather than as differing in colour. Papilio butterflies are clearly able to use at least two modes of polarization vision depending on the behavioural context.

scholarly journals Studies on gonadosomatic index, fecundity and hatchability of domesticated stock of asala Schizothorax richardsonii (Gray) from Nallu River of Lalitpur District

Our Nature ◽  
2015 ◽  
Vol 12 (1) ◽  
pp. 19-27
Author(s):  
Suresh Kumar Wagle
Keyword(s):  
Water Temperature ◽  
Egg Size ◽  
Gonadosomatic Index ◽  
Winter Season ◽  
Summer Season ◽  
Reproductive Capacity ◽  
Schizothorax Richardsonii ◽  
Breeding Seasons ◽  
Frequent Observation ◽  
Hatching Rates

The present work embodies studies on the reproductive capacity of captive stock of asala Schizothorax richardsonii collected from Nallu River of Lalitpur district. Gonadosomatic index (GSI) estimates ranged from 3.08±0.9% in May to 26.55±1.8% in November. Positive correlation (r=0.667) was found between egg size and GSI. The egg size (2.7 to 2.9 mm) in October and November was significantly (P<0.01) larger than the eggs measured in other months. Based on peak GSI level, S. richardsonii spawned by manual stripping in two breeding season i.e. winter (October-November) and summer (Mach-April) in Godawari (1500 masl). Mean incubation period of fertilized eggs was 259 h and 248 h during winter and summer season at 14.2 to17.5 oC and 14.5 to15.5 oC water temperature, respectively. Percent hatching rates of eggs ranged between 38 to 90% and were not significantly different (P>0.05) between breeding seasons. Overripe eggs obtained during winter season breeding (16.5%) were significantly higher (P<0.01) than the summer season breeding (3.6%).  This suggests that more frequent observation of the spawner is necessary during winter season for recognizing their appropriateness to ovulation. DOI: http://dx.doi.org/10.3126/on.v12i1.12253Our Nature (2014), 12(1): 19-27

Annual Productivity and Its Measurement in a Multi-Brooded Passerine, the Eastern Bluebird

The Auk ◽  
1979 ◽  
Vol 96 (3) ◽  
pp. 562-572
Author(s):  
Benedict C. Pinkowski
Keyword(s):  
Success Rate ◽  
Age Groups ◽  
Nesting Success ◽  
Egg Laying ◽  
Success Rates ◽  
Sialia Sialis ◽  
Eastern Bluebird ◽  
Annual Productivity ◽  
Eastern Bluebirds ◽  
Breeding Seasons

Abstract Breeding and demographic parameters are examined for 434 Eastern Bluebirds (Sialia sialis) attempting 324 nests in southeastern Michigan during 1968-1977. Nesting birds spent an average of 10.4 weeks (63.9% of a 16.2-week season) in the study area. Only 154 (35.5%) of the nesting birds remained for entire breeding seasons; these season-long residents averaged 2.14 nests/season and had a higher success rate (68.4%) and presumably greater productivity (5.6 young · pair−1 · season −1) than other birds because site fidelity depends on nesting success. Although two seasonal peaks for egg-laying were observed, only 75 of 357 birds (21.0%) successfully raised two broods. Evidence is presented to suggest that birds observed for only part of a season initiated nests at the same rate while in and not in the study area, so that an average annual productivity value of 5.0 young · pair−1 · season −1 is calculated for all nesting birds from the observed success rate (57.1%) and mean length of stay in the area. Estimated average productivity of yearlings (4.3 young · pair−1 · season −1) was lower than that of adults (5.7 young · pair−1 · season −1) although nesting success rates were similar in the two age groups.

Factors affecting wing molt chronology of female mallards

1991 ◽  
Vol 69 (4) ◽  
pp. 924-928 ◽  
Author(s):  
James O. Leafloor ◽  
C. Davison Ankney
Keyword(s):  
Social Environment ◽  
Positive Relationship ◽  
Anas Platyrhynchos ◽  
Nest Success ◽  
Breeding Period ◽  
Social Environments ◽  
Mortality Factors ◽  
Factors Affecting ◽  
Breeding Seasons

We manipulated nest success of captive mallards (Anas platyrhynchos) during two breeding seasons to determine the effects of different breeding events on the timing of wing molt initiation in females. We also studied the effect of different social environments during the postbreeding period on female wing molt chronology. Late (renesting) brood hens molted their remiges later than did early brood hens in both years of the study. Unsuccessful nesters showed a late, asynchronous wing molt when they molted solitarily, but an early, synchronous wing molt when they were placed together during the postbreeding period. There was a positive relationship between the last date of incubation and the date of wing molt initiation when birds were placed in a group after the breeding period. Social environment appeared to influence the timing of wing molt, particularly among unsuccessful nesters. We discuss the implications of these results in terms of postbreeding mortality factors and potential fall banding bias.

Annual variation in common eider egg size: effects of temperature, clutch size, laying date, and laying sequence

1995 ◽  
Vol 73 (9) ◽  
pp. 1579-1587 ◽  
Author(s):  
Gregory J. Robertson
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Annual Variation ◽  
Size Variation ◽  
Egg Laying ◽  
Laying Date ◽  
Somateria Mollissima ◽  
Ambient Temperatures ◽  
Common Eiders ◽  
N 93

Annual variation in volumes of eggs laid by common eiders (Somateria mollissima sedentaria) nesting at La Pérouse Bay, Manitoba (58°43′N, 93°27′W), was studied over 3 years (1991–1993). Temperatures during the egg-laying period were higher in 1991 than in 1992 and 1993. However, the eiders began nesting in 1993 at the same time as in 1991, whereas in 1992 the eiders began laying approximately 2 weeks later. Eiders laid significantly smaller clutches in 1992 than in the other 2 years. Egg size did not correlate with clutch size or laying date in any year. However, eiders laid smaller eggs in 1992 and 1993 than in 1991. In five egg clutches, the pattern of intraclutch egg-size variation was different among years. The last laid eggs of five egg clutches were disproportionately smaller in 1992 and 1993 (cold years) than those laid in 1991. Minimum daily temperatures before the egg-laying period (during rapid yolk development) were positively correlated with egg size. However, this effect was not significant when year and egg sequence were controlled for. Egg-size variation was correlated with the overall ambient temperatures during the laying period, whereas annual clutch-size variation was correlated with laying date, suggesting that the proximate mechanisms affecting clutch and egg size are different.

The European Rabbit in South-Western Australia. I. Study Sites and Population Dynamics.

1985 ◽  
Vol 12 (2) ◽  
pp. 183 ◽  
Author(s):  
DR King ◽  
SH Wheeler
Keyword(s):  
Biological Control ◽  
Western Australia ◽  
Biological Control Agent ◽  
Control Agent ◽  
European Rabbit ◽  
Breeding Period ◽  
South West ◽  
Study Sites ◽  
Breeding Seasons ◽  
Winter Rain

Descriptions are given of 2 study sites in the south-west of Western Australia, on which rabbit numbers were monitored. Breeding seasons began in March or April, with the onset of winter rain, and rabbit numbers peaked in October-December, followed by a fall over the non-breeding period in summer. Winter epizootics of myxomatosis, which were spread by Spilopsyllus cuniculi, caused severe declines in rabbit numbers at both sites. Summer epizootics at one site before the introduction of the flea as a biological control agent, and rabbit mortality during these, was lower than in the winter epizootics.

Investigations on Trichogramma lutea, Gir., as a Parasite of the Cotton Bollworm, Heliothis obsoleta, Fabr.

1936 ◽  
Vol 27 (2) ◽  
pp. 219-235 ◽  
Author(s):  
F. S. Parsons ◽  
G. C. Ullyett
Keyword(s):  
Winter Season ◽  
Larval Survival ◽  
Egg Laying ◽  
Mortality Factors ◽  
Cool Season ◽  
Large Numbers ◽  
Typical Experiment ◽  
Egg Parasitism ◽  
Citrus Orchards ◽  
Low Degrees

Some of the problems involved in the estimation of parasitism in populations of Heliothis eggs are discussed:—(a) Effective parasitism of the “active fraction” of eggs as laid in situ is denned.(b) The habits of the egg-laying moth in point of the duration of oviposition on individual crops and diversion of moth activity from one host to another are discussed in relation to releases of Trichogramma lutea. Data are given on the distribution of bollworm eggs in a crop and associated factors.(c) Investigations on the dispersion of liberated parasites are described. Dispersion was found to be rapid and widespread; concerted activity by large numbers in given areas did not apply.Investigations in rain-grown crops are described and results are quoted from a typical experiment in maize, wherein the percentages of parasitism recorded in a large number of equal sections of the crop are regressed on proportionate larval survival. Although the egg parasitism ranged from 21·2 per cent, to 82·3 per cent., differences in larval populations were inappreciable. An explanation for this is offered in an analysis of the effect of various mortality factors.The parasite was relatively ineffective in cotton crops. The low degrees of parasitism found are assigned to the growth-habit of the plant, the scattered manner of egg deposition thereon and the impediment offered to the insect by the dense hair processes of the plant at many sites where eggs are commonly placed.Investigations on irrigated (cool season) market-garden crops and citrus orchards are described. These form the principal breeding sources of summer bollworm. Oviposition is extensive and sustained for three to four months on these crops, thereby affording opportunity for continuous parasite activity and the cumulative participation of progeny bred in the field. In nature Trichogramma lutea does not, however, appear until the latter end of the egg-laying by Heliothis and the authors were unable to establish laboratory-bred representatives at an earlier period.Another egg parasite, Phanurus ullyetti, is prevalent before Trichogramma appears and accomplishes much that was hoped for from the attempted earlier introduction of Trichogramma. In effect, the latter, as seen from diagrams furnished with the paper, becomes substituted for Phanurus toward the close of the winter season. It is probable that temperature is a determining factor in the biology of both parasites, although other causes for the observed relations are suggested.Further investigations are needed on the subject of exploiting T. lutea in the cool season.

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