Patterns of Egg Laying and Breeding Success in Humboldt Penguins (Spheniscus Humboldti) at Punta San Juan, Peru

Abstract We analyzed patterns of egg laying and breeding frequency of Humboldt Penguins (Spheniscus humboldti) between 1993 and 1997 at Punta San Juan, Peru. Egg-laying extended from mid-March to the first week of December, showing two well-defined peaks in April and August–September. The extended breeding period of these birds was the result of individuals having a second clutch. About half of the females (n =189) had two clutches per year, most of which were double broods (73%). The date of completion and outcome of reproduction, or whether a change of mates occurred from the previous year, did not affect timing of egg laying. The majority of first clutches (62%) were laid in April each year. Two-clutch breeders that started laying eggs early in April had a higher breeding success than those starting in late April, and double brooders had greater success than single brooders. Two-clutch breeders started to lay eggs earlier than single-clutch breeders. Taking into account that a penguin breeding cycle (from egg laying to fledging) lasts ∼4 months, laying eggs early in April increases the chance of rearing two successful broods per year. During three consecutive years, females tended to have two clutches instead of only one clutch and an average breeding success of 4.54 fledglings over 3 years. Having as many clutches as possible when conditions are favorable appears to be a strategy used by Humboldt Penguins to maximize their lifetime reproductive success within a productive but unpredictable environment.

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Breeding Biology of the Puerto Rican Sharp-Shinned Hawk (Accipiter Striatus Venator)

The Auk ◽

10.1093/auk/105.4.649 ◽

1988 ◽

Vol 105 (4) ◽

pp. 649-662 ◽

Cited By ~ 26

Author(s):

Carlos A. Delannoy ◽

Alexander Cruz

Keyword(s):

Puerto Rico ◽

Reproductive Success ◽

Breeding Population ◽

Egg Laying ◽

Breeding Biology ◽

Breeding Cycle ◽

Territorial Conflicts ◽

Nesting Sites ◽

Accipiter Striatus ◽

Breeding Attempt

Abstract We studied the breeding biology of the Sharp-shinned Hawk (Accipiter striatus venator ) in Maricao forest of western Puerto Rico from 1978 to 1985. Sharp-shinned Hawks are year-round residents and establish nesting territories only during the breeding season, which coincides with the dry and beginning of the wet seasons. Nesting sites were occupied in December and January every year and reoccupancy rates were 50% or higher. Prolonged and intense territorial conflicts between mated and unmated males were common. The onset of egg-laying was in late March or early April approximately 3-4 months after occupancy of nesting sites. Laying of first clutches peaked in early April and spanned 38 days (n = 19 clutches). Laying of second clutches occurred irregularly and spanned 55 days (n = 8 clutches). Females renested only after the initial clutch or brood was lost. The incubation period was 32 days (n = 13 clutches), similar to the duration reported in temperate North America. Nestling females attained larger asymptotic mass than males, but the latter grew faster; although the slopes of the regression lines were statistically homogeneous. Males fledged at an average age of 28.2 days and females at 32.1 days. Young were slightly heavier than adults at fledging, but the wing chord and tail lengths were approximately 50% shorter than those of adults. Fledging occurred at the peak of prey abundance. The breeding cycle in Puerto Rico was approximately 2 months longer than that recorded in Oregon and Utah. The time that elapsed from occupancy of nesting sites to egg laying accounted for the differences. Juveniles departed from nesting sites when prey was still abundant but delivery rates had declined considerably. A total of 105 eggs was laid in 40 nests (average clutch size 2.6), of which 63% hatched and 47% of the nestlings fledged. A total of 0.8 young fledged per breeding attempt. Overall nest success was 29%, 36% (n = 33 nests) in first nesting attempts and 0% in second nesting attempts (n = 9 nests). Most reproductive losses in 28 nests resulted from nestling mortality from Philornis sp. (Diptera, Muscidae) (n = 9) and desertion of clutches (n = 11). Fecundity and reproductive success was lower in Puerto Rico than in Oregon, Utah, and Wyoming. Despite low reproductive success in Maricao forest, the breeding population did not decline during our study.

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Migratory Dates, Breeding Phenology, and Reproductive Success of European Turtle Doves between Lowlands and Highest Breeding Habitats in North Africa

International Journal of Zoology ◽

10.1155/2020/8816577 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Ismail Mansouri ◽

Mohamed Mounir ◽

Wafae Squalli ◽

Laila Elhanafi ◽

Mohamed Dakki ◽

...

Keyword(s):

Reproductive Success ◽

Breeding Success ◽

Breeding Site ◽

Breeding Habitat ◽

Breeding Period ◽

Breeding Phenology ◽

Climate Conditions ◽

Turtle Dove ◽

Beni Mellal ◽

Low Altitude

The migratory time, breeding chronology, and reproductive success of the European turtle doves (Streptopelia turtur) were studied in Midelt as a high-altitude breeding habitat and Beni Mellal as a low-altitude breeding site from 2015 to 2018 in Morocco. Migration dates, breeding phenology, and breeding success were recorded from March to October for each season. As a result, during four years, arrival dates were earlier at the low breeding site, while departure dates were earlier at the high breeding site. Similarly, breeding phenology from nest building to fledging was early at low-altitude site. On the other hand, with four breeding seasons and 893 nests (467 at Midelt and 426 at Beni Mellal), average breeding success was 57% of chicks at Midelt compared to 60.15% at Beni Mellal. Moreover, at Midelt, 18.89% of eggs and 10.54% of chicks were predated, while at Beni Mellal 21.80% of eggs and 4.65% of chicks were deserted due to human disturbance. As a response, at Midelt breeding period was shorter and shifted to hot periods to ensure better reproductive success. Finally, our results highlight that the turtle dove breeding season is later and shorter at breeding highlands, which might allow this bird to avoid the vigorous climate conditions at mountains and their effect on reproductive success.

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The influence of age on reproductive success and diet in Australasian gannets (Morus serrator) breeding at Pope's Eye, Port Phillip Bay, Victoria

Australian Journal of Zoology ◽

10.1071/zo06088 ◽

2007 ◽

Vol 55 (5) ◽

pp. 267 ◽

Cited By ~ 5

Author(s):

T. M. Pyk ◽

A. Bunce ◽

F. I. Norman

Keyword(s):

Reproductive Success ◽

Food Availability ◽

Fish Species ◽

Breeding Success ◽

Breeding Period ◽

Chick Growth ◽

Jack Mackerel ◽

Commercial Fish ◽

Red Mullet ◽

Morus Serrator

The influence of age on reproductive success and diet was examined in ‘old’ (experienced; 12 years and older) and ‘young’ (5–8 years of age) Australasian gannets (Morus serrator) breeding at Pope’s Eye, Port Phillip Bay, Victoria during the 2002–2003 breeding period. Although food availability, as indicated by commercial fish catches, throughout this breeding period was low, there were no significant differences in breeding success or chick growth between groups. Nevertheless, old birds tended to have higher reproductive success, replacing more lost eggs and fledging chicks of a greater mass. However, old birds also laid more eggs that failed to hatch. Five fish species, including jack mackerel (Trachurus declivis), barracouta (Thyrsites atun), redbait (Emmelichthys nitidus), anchovy (Engraulis australis) and red mullet (Upeneichthys vlamingii), were important in the gannet diet during this breeding period. There were no significant differences in dietary parameters, including range of species and size of prey, between old and young gannets, nor were there any differences between those of the chicks and their parents, suggesting that adults do not forage selectively for their chicks. This study showed that even during a period of presumed low food availability, when experienced (older) birds might be expected to have enhanced success, the differences between these and less experienced (younger) birds may not be apparent.

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Lifetime Reproductive Success of Bald Eagles in Northern California

The Condor ◽

10.1093/condor/108.3.730 ◽

2006 ◽

Vol 108 (3) ◽

pp. 730-735

Author(s):

J. Mark Jenkins ◽

Ronald E. Jackman

Keyword(s):

Survival Rate ◽

Reproductive Success ◽

Breeding Success ◽

Breeding Birds ◽

Nesting Success ◽

Lifetime Reproductive Success ◽

Haliaeetus Leucocephalus ◽

Northern California ◽

Bald Eagles ◽

Occupied Territory

Abstract We studied the breeding success of resident Bald Eagles (Haliaeetus leucocephalus) over a 20-year period along the Pit River drainage in northern California. In 258 nesting attempts at 10 intensively studied nesting territories, 0.31 to 1.65 young were produced per year per occupied territory (mean = 0.97), with average nesting success of 62%. Nineteen individually banded breeding adult Bald Eagles produced from zero to 36 young during their lifetimes, and birds remained on their territories for 1–16 years following capture as adults. We calculated a 90% annual survival rate for breeding adults from our sample of 19 birds, with longevity of one banded eagle at 22 years. Eagles that bred on a territory for a greater number of years did not produce a greater number of young annually on average than other breeding birds. Larger males, as evidenced by body mass at capture, produced significantly more young over their lifetimes than smaller males. This same relationship did not hold for females, however. Seven banded pairs of adults remained together on their territories for 3–15 years. Reproduction decreased significantly following replacement of a breeding adult on a territory, and this effect continued for 2–3 years following replacement.

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Lifetime reproductive success is maximized with optimal major histocompatibility complex diversity

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2008.1466 ◽

2008 ◽

Vol 276 (1658) ◽

pp. 925-934 ◽

Cited By ~ 97

Author(s):

Martin Kalbe ◽

Christophe Eizaguirre ◽

Ilka Dankert ◽

Thorsten B.H Reusch ◽

Ralf D Sommerfeld ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Reproductive Success ◽

Mhc Class Ii ◽

Gasterosteus Aculeatus ◽

Natural Populations ◽

Lifetime Reproductive Success ◽

Breeding Period ◽

Major Histocompatibility ◽

Histocompatibility Complex ◽

Mhc Diversity

Individual diversity at the major histocompatibility complex (MHC) is predicted to be optimal at intermediate rather than at maximal levels. We showed previously in sticklebacks that an intermediate MHC diversity is predominant in natural populations and provides maximal resistance in experimental multiple parasite infections in the laboratory. However, what counts ultimately is the lifetime reproductive success (LRS). Here, we measured LRS of six laboratory-bred sib-groups—to minimize the influence of non-MHC genes—three-spined sticklebacks ( Gasterosteus aculeatus ) during their entire breeding period, each in a seminatural enclosure in the lake of their parents, where they were exposed to the natural spectrum of parasites. We collected developing clutches at regular intervals and determined parenthood for a representative number of eggs (2279 in total) per clutch with 18 microsatellites. Both males and females with an intermediate MHC class II B variant number had the highest LRS. The mechanistic link of MHC diversity and LRS differed between the sexes: in females, we found evidence for a trade-off between number of eggs and immunocompentence, whereas in males this correlation was concealed by different timing strategies of reproduction.

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Natal conditions, lifespan and lifetime reproductive success of European blackbirds

Behavioral Ecology ◽

10.1093/beheco/arz139 ◽

2019 ◽

Vol 30 (6) ◽

pp. 1707-1714

Author(s):

Dariusz Wysocki ◽

Łukasz Jankowiak ◽

Marta Cholewa ◽

Dawid Zyskowski

Keyword(s):

Reproductive Success ◽

Daily Precipitation ◽

Weather Conditions ◽

Complete Information ◽

Egg Laying ◽

Laying Date ◽

Lifetime Reproductive Success ◽

Long Term Study ◽

Bird Density ◽

Pair Density

Abstract Even though much has been published in recent years on the factors affecting the lifespan and lifetime reproductive success of birds, there are still gaps in our knowledge. Here, we present the results of a long-term study of European blackbirds which examined the effect of natal conditions on lifespan and lifetime reproductive success (expressed by the number of fledglings) of 152 nestlings (72 males and 80 females) ringed in the Stefan Żeromski Park in Szczecin (NW Poland). We have complete information regarding parental age, family brood (first-egg laying date, clutch size, and hatching sequence), bird size, lifetime reproductive success, pair density and weather conditions during the natal year. For males, total fledgling production was the smaller, the later the laying date of the family brood, but increased with mean daily precipitation and pair density in the natal year. In the case of females, we did not find any significant relationships between their lifetime reproductive success and the above parameters. Male lifespan increased with mean daily precipitation and bird density, but only pair density had a positive effect on female lifespan. We suggest that for females, genetic factors could be more important for their reproductive success than for males. In addition, a blackbird’s lifespan depends strongly on environmental factors.

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