scholarly journals Reproduction and Survival in a Variable Environment: Ural Owls (Strix Uralensis) and the Three-Year Vole Cycle

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 544-550 ◽  
Author(s):  
Jon E. Brommer ◽  
Hannu Pietiäinen ◽  
Heikki Kolunen
Keyword(s):  
Reproductive Output ◽  
Breeding Population ◽  
Laying Date ◽  
Variable Environment ◽  
Paradoxical Situation ◽  
Vole Cycle ◽  
Regional Abundance ◽  
Previous Autumn ◽  
Ural Owl ◽  
Population Numbers

Abstract We analyzed data on 535 Ural Owl (Strix uralensis) breeding attempts and consecutive survival of both adults and offspring from 1987–1998 in relation to the regional abundance of the Ural Owl's main prey, voles, which show a cycle of low, increase, and peak phases in their population numbers. Vole abundance varied up to 49×, crashing during spring–summer every three years. The breeding population tracked abundance of voles in the previous autumn with respect to percentage of pairs breeding and their reproductive output (laying date, clutch size), largely irrespective of phase. Survival depended on vole density in the preceding autumn, but was generally highest in the increase phase. There was thus a paradoxical situation in the peak phases, when vole populations crashed; the owls produced large clutches, but those survived poorly. Some adaptive and nonadaptive scenarios of the Ural Owl's life history are discussed.

The status of Gould's petrel, Pterodroma leucoptera leucoptera, on Cabbage Tree Island, New South Wales

1995 ◽  
Vol 22 (5) ◽  
pp. 601 ◽  
Author(s):  
D Priddel ◽  
N Carlile ◽  
C Davey ◽  
P Fullagar
Keyword(s):  
Reproductive Output ◽  
New South ◽  
New South Wales ◽  
Breeding Population ◽  
Tree Island ◽  
South Wales ◽  
The Status ◽  
Marginal Improvement ◽  
Main Population ◽  
Cabbage Tree

Gould's petrel, Pterodroma leucoptera leucoptera, breeds only on Cabbage Tree Island, New South Wales. Annual surveys to estimate the size of the breeding population and the reproductive output were conducted between 1989 and 1992. Annual estimates of the total number of pairs breeding in the two gullies containing the main population were between 122 +/- 20 (s.e.) and 202 +/- 26. Breeding success was less than 20% between 1989 and 1991, but rose to 24.7% in 1992. This marginal improvement may be the result of management action undertaken to reduce mortality of breeding adults and fledglings. The total population is estimated to have declined from 2004 (95% confidence limits: 1464,3185) in 1970 to 1479 (1250,1815) in 1992, a decline of 26% in 22 years. The reasons for this decline are unclear.

Effects of body mass on courtship, pairing, and reproduction in captive mallards

1989 ◽  
Vol 67 (2) ◽  
pp. 495-501 ◽  
Author(s):  
R. K. Pattenden ◽  
D. A. Boag
Keyword(s):  
Clutch Size ◽  
Body Mass ◽  
Reproductive Output ◽  
Breeding Biology ◽  
Laying Date ◽  
Body Reserves ◽  
Pair Bonds ◽  
Breeding Grounds ◽  
Delayed Initiation ◽  
Nutrient Reserves

The object of this study was to examine the influence of body mass, a measure of nutrient reserves, on the breeding biology of captive mallards. Low body mass delayed initiation of courtship and pairing, and decreased the number of permanent pair bonds formed. However, pairing date was not correlated with laying date. Low body mass during winter had a greater influence on laying date than low body mass during spring, but neither affected clutch size. This suggests that an individual arriving on the breeding grounds with low body reserves relative to others will have a lower reproductive output that year.

scholarly journals Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Laying Date ◽  
Egg Mass ◽  
Size Number ◽  
Female Reproductive Traits ◽  
Clutch Mass

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

Food shortage for breeding Black-billed Magpies (Pica pica): an experiment using supplemental food

1987 ◽  
Vol 65 (5) ◽  
pp. 1270-1274 ◽  
Author(s):  
Wesley M. Hochachka ◽  
David A. Boag
Keyword(s):  
Breeding Population ◽  
Egg Laying ◽  
Food Shortage ◽  
Laying Date ◽  
Food Supplementation ◽  
Natural Food ◽  
Supplemental Feeding ◽  
Pica Pica ◽  
Supplemental Food ◽  
Before And After

Supplemental food was provided to a breeding population of Black-billed Magpies (Pica pica), starting before and after eggs were laid, to determine if and when natural food was limited. The production of fledgling magpies was increased only when supplemental feeding was begun before laying. Laying date was also advanced when supplemental feeding began before laying, but clutch and egg size were not significantly changed. Because the two feeding treatments were conducted in different years, we cannot conclude whether natural food was limiting before or after egg laying. However, out data suggest that the former may have been the case. An improved design for food supplementation experiments, which can be used to determine the time of food shortage, is suggested.

Lower reproductive output of Mountain Bluebirds (Sialia currucoides) in clearcut versus grassland habitat is consistent with a passive ecological trap

2019 ◽  
Vol 97 (10) ◽  
pp. 895-903 ◽  
Author(s):  
J.A. Stalwick ◽  
K.L. Wiebe
Keyword(s):  
Body Condition ◽  
Reproductive Output ◽  
Grassland Birds ◽  
The Body ◽  
Ecological Trap ◽  
Laying Date ◽  
Sialia Currucoides ◽  
Mountain Bluebirds ◽  
Predation Rates

Clearcutting of forests results in habitats that structurally resemble grasslands and so may act as ecological traps for grassland birds. Several studies have implicated predation as the factor that decreases the number of offspring, but few have examined performance at other breeding stages. Consistent with a passive ecological trap, Mountain Bluebirds (Sialia currucoides (Bechstein, 1798)) that settled in clearcuts in central British Columbia did not differ in age or quality from adults in grasslands. Nest building and laying date of the first egg did not differ between habitats, suggesting an equal propensity for settling in each habitat. In clearcuts, however, the body condition of female parents was lower, and they abandoned their nests more often in harsh weather. This higher total clutch loss in clearcuts meant that seasonal production of fledglings per female was 13% less in clearcuts. Furthermore, fledglings in grasslands weighed 4% more and female fledglings had plumage with shorter (UV-shifted) wavelengths (hence greater ornamentation) than those in clearcuts, suggesting that they were also of better quality. Thus, predation rates were not the cause of reduced reproduction in clearcuts; rather, our results suggest that lower prey abundance was linked to nest abandonment in harsh weather and reduced both the number and quality of offspring in those habitats.

scholarly journals Seasonal Egg-Mass Variation and Laying Sequence in a Bird With Facultative Brood Reduction

The Auk ◽  
2007 ◽  
Vol 124 (2) ◽  
pp. 643-652 ◽  
Author(s):  
Liliana D'Alba ◽  
Roxana Torres
Keyword(s):  
Reproductive Output ◽  
Brood Reduction ◽  
Laying Date ◽  
Egg Mass ◽  
Chick Survival ◽  
Mass Variation ◽  
Embryo Survival ◽  
Sula Nebouxii ◽  
Laying Order ◽  
Laying Sequence

Abstract Females may maximize their lifetime reproductive output by adjusting their investment in each breeding event to the perceived likelihood of success. The Blue-footed Booby (Sula nebouxii) is a long-lived seabird with facultative siblicide. We examined whether there is differential resource allocation to eggs with laying order and whether greater egg mass increases hatching probability, chick survival, hatching interval, and mass and size at hatching. We found that the relative investment in first and second eggs decreased as the season advanced: second eggs were slightly (1.5%) heavier than first eggs in early clutches; by contrast, first eggs were 2% heavier than second eggs in late clutches. Accordingly, hatching probability increased with laying date for first eggs and decreased for second eggs. The mass of the egg increased hatching probability, and no effect on chick survival was detected. Laying interval increased after a heavier egg was laid, and heavier eggs produced heavier hatchlings. Hatching intervals were positively related to laying intervals, but egg mass was unrelated to the length of the incubation period and the hatching interval. Our results suggest that egg mass influences embryo survival and that Blue-footed Booby females may adaptively allocate resources to eggs of different laying order according to breeding conditions. Variación del Peso de los Huevos y Secuencia de Postura en un Ave con Reducción Facultativa de la Nidada

scholarly journals Change in Historical Range of the Ural Owl in Europe

2020 ◽  
Vol 146 (1) ◽  
Author(s):  
Quentin Goffette ◽  
Marceline Denis ◽  
Nadja Pöllath ◽  
Wim Van Neer
Keyword(s):  
Breeding Population ◽  
Medieval Period ◽  
Western Palearctic ◽  
First Occurrence ◽  
Local Breeding ◽  
Natural Breeding ◽  
The Town ◽  
Historical Range ◽  
Ural Owl ◽  
Rule Out

A carpometacarpus recovered during archaeological excavations in the town of Quaregnon is the westernmost find ever reported in Europe of a Ural Owl (Strix uralensis), and the first occurrence for Belgium. Both the morphology of the skeletal element and its measurements rule out an identification as any of the other Strigiformes from the Western Palearctic. The provenance of this specimen, that dates to the medieval period (10th-12th centuries AD), is discussed. It is hypothesized that the bird was a wild animal, but the available evidence does not unequivocally determine whether it belonged to a local, breeding population that went extinct or if it came from a more distant population. However, a survey of other zooarchaeological finds of Ural Owl in Europe shows that the species occurred farther west in the past, outside the present natural breeding range. This suggests that Ural Owl may have found suitable nesting biotopes in Belgium and northern France during the medieval period.

Delayed timing of breeding attempts, but not time lost to nest construction, reduces the annual reproductive output of the Eastern Phoebe (Sayornis phoebe)

2021 ◽  
pp. 175815592110660
Author(s):  
Janice K Enos ◽  
Mark E Hauber ◽  
Zachary Aidala
Keyword(s):  
Parental Care ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Experimental Treatment ◽  
Egg Laying ◽  
Laying Date ◽  
Nest Construction ◽  
Sayornis Phoebe ◽  
Initial Onset ◽  
Breeding Seasons

For many birds, nest construction is a costly aspect of parental care, trading finite energetic resources between parental care and self-maintenance. For multi-brooded organisms with short breeding seasons, such as migratory passerines, repeated nest construction could be especially costly if the activity delays the onset of breeding attempts. Earlier studies on passerines that reuse nests between breeding seasons suggested that time lost to initial nest construction reduces seasonal reproductive output. However, costs associated with building new nests between breeding attempts, within the same breeding season, have largely been ignored. Here, we experimentally removed first nests, after fledging or failing, of Eastern Phoebes ( Sayornis phoebe), to evaluate how the annual onset of breeding and nest construction between breeding attempts affected parental investment into second attempts. We found that first egg laying date negatively predicted the probability of second breeding attempts, but experimental treatment (first nest removal vs. control) did not. Neither first egg laying date nor treatment statistically influenced any of the reproductive traits in second breeding attempts (clutch size, nestling body condition, and nestling growth rate). We conclude that in this species, second breeding attempts are limited by the initial onset of seasonal reproduction, and not by time lost to nest construction between breeding attempts.

Nesting of northern pintails in Alberta: laying date, clutch size, and renesting

1987 ◽  
Vol 65 (2) ◽  
pp. 234-246 ◽  
Author(s):  
David C. Duncan
Keyword(s):  
Clutch Size ◽  
Reproductive Output ◽  
Wild Birds ◽  
Laying Date ◽  
Strongly Correlated ◽  
Southern Alberta ◽  
In The Wild ◽  
Proximate Causes ◽  
Northern Pintails ◽  
Seasonal Decline

Nesting of northern pintails was studied in southern Alberta where breeding densities are high. Adults nested earlier and laid larger clutches than did yearlings in the wild. Captive pintails nested earlier, laid larger clutches, and appeared to renest more readily than did wild birds. Food may limit each of these parameters in the wild. The reproductive output of female pintails nesting in high densities in southern Alberta appears to be lower than that of birds breeding at Delta, Manitoba, because of reduced clutch size and lower renesting rate. Clutch size was strongly correlated with laying date but the laying of larger clutches by adults in the wild (and by captive birds relative to wild birds) was not simply a consequence of earlier nesting. A number of proximate causes suggested to explain the seasonal decline in clutch size (hen age, renesting, declining food resources, and decreased body reserves) were rejected. Whatever the mechanism through which laying date influences clutch size, the ultimate reason for this phenomenon may be a seasonally declining survival rate of young which has selected for reduced reproductive effort later in the breeding season. Captive pintails fed a 14% or 29% protein diet after laying their first clutches did not differ in frequency of renesting, clutch size, or renest interval.

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