New Nesting Records and Breeding Ecology Observations of Rufous-legged Owls in the Mediterranean Temperate Forest of Central Chile

ABSTRACT The Rufous-legged Owl (Strix rufipes) is the southernmost Strix owl species and its breeding ecology remains little known. We report new observations on the species' breeding ecology, including clutch size, egg size, duration of the incubation and nestling periods, and nestling diet. We conducted our observations on nests found during the summers of 1999 through 2004 in a forestry landscape of central Chile, dominated by Monterey pine (Pinus radiata) plantations with intermixed fragments of native southern beech (Nothofagus) forests. Clutch size was two eggs (n = 2 nests), with one egg larger than the other (mean = 48.8 × 40.1 mm). The incubation period was 30 d and the nestling period 34 d. We analyzed 10 pellets from nestling owls and identified 45 prey items, mostly dominated by large beetles, grasshoppers, and rodents (native and exotic). This information, though based on a limited number of nests, provides baseline ecological data that can inform future studies.

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Behavior, Diet, and Breeding Biology of Double-Toothed Kites at a Guatemalan Lowland Site

The Condor ◽

10.1093/condor/102.1.113 ◽

2000 ◽

Vol 102 (1) ◽

pp. 113-126 ◽

Cited By ~ 1

Author(s):

Mark D. Schulze ◽

Jose LuÍs CÓrdova ◽

Nathaniel E. Seavy ◽

David F. Whitacre

Keyword(s):

Clutch Size ◽

Rainy Season ◽

National Park ◽

Maximum Density ◽

Lowland Forest ◽

Tropical Lowland ◽

Nestling Diet ◽

Tropical Lowland Forest ◽

Nestling Period ◽

Closed Canopy

Abstract We studied Double-toothed Kites (Harpagus bidentatus) in tropical lowland forest at Tikal National Park, Petén, Guatemala, documenting behavior and diet during the incubation and nestling periods. These 200-g kites are Accipiter-like in form and strikingly size-dimorphic for a kite. Modal clutch size was two, producing 0.63 fledglings per nesting attempt and 1.25 per successful nest. Nesting was largely synchronous among pairs, with hatching during the first month of the rainy season and fledging one month later. Incubation lasted 42–45 days and nestlings fledged at 29.5 days on average. A radio-tagged fledgling was fed near the nest for 35 days; 6–8 weeks after fledging it dispersed at least 10 km, presumably reaching independence. Males did not incubate or brood, and rarely fed nestlings directly. Males typically provided most but not all prey (mainly lizards) during incubation and early nestling periods. Insects in the nestling diet increased through the nestling period as females increasingly hunted, often bringing in insects. These kites hunted from perches, below and within the closed canopy of tall, mature forest, taking 60.5% insects, 38.1% lizards, and 1.4% other vertebrates; vertebrates comprised at least 75% of prey biomass. Most prey were taken from vegetation, but prey in flight also were captured. Active, adjacent nests averaged 1.35 km apart, for a maximum density estimate of 0.60 pairs km−2 and a more likely estimate of 0.33–0.50 pairs km−2 in homogeneous, favorable habitat and 0.29–0.44 pairs km−2 for Tikal National Park as a whole.

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Clutch Enlargement in Lesser Gray Shrikes (Lanius Minor) in Slovakia When Food is Superabundant: A Maladaptive Response?

The Auk ◽

10.1093/auk/121.2.557 ◽

2004 ◽

Vol 121 (2) ◽

pp. 557-564

Author(s):

Herbert Hoi ◽

Anton Kristin ◽

Francisco Valera ◽

Christine Hoi

Keyword(s):

Clutch Size ◽

Egg Laying ◽

Laying Date ◽

Breeding Ecology ◽

Long Distance ◽

Fledging Success ◽

Melolontha Melolontha ◽

Nestling Diet ◽

Study Population ◽

Maladaptive Response

Abstract Food abundance influences various aspects of birds' breeding ecology, such as onset of laying, clutch size, and reproductive success. Here, we examine the effects of a natural superabundance of food—cockchafers (Melolontha melolontha, Coleoptera)—on nesting success of a monogamous long-distance migrant, the Lesser Gray Shrike (Lanius minor). In that species, cockchafers make up 88% of adult and 48% of nestling diet in years with cockchafer outbreaks. We compared timing of egg laying, clutch size, and fledging success in three years and chick development in two years with and without cockchafer outbreaks. In cockchafer years, laying date was advanced by about one day, clutch size increased by about one egg, and heavier chicks were produced. Fledging success, however, did not change (fledgling number in non-cockchafer years: 5.3 ± 0.2, 5.0 ± 0.2, and 4.0 ± 0.5; in cockchafer years: 4.1 ± 0.7, 5.4 ± 0.2, and 4.2 ± 0.5), because more eggs failed to hatch during cockchafer years. Thus, increased clutch size in periods of superabundant food do not always result in increased fledgling production. Limited incubation ability or intrinsic physical egg properties, resulting in inefficient incubation, are the most likely explanations for increased hatching failure in years of food superabundance in our study population of Lesser Gray Shrikes.

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Tri-axial accelerometry shows differences in energy expenditure and parental effort throughout the breeding season in long-lived raptors

Current Zoology ◽

10.1093/cz/zoab010 ◽

2021 ◽

Author(s):

Pascual LÓPEZ-LÓPEZ ◽

Arturo M PERONA ◽

Olga EGEA-CASAS ◽

Jon ETXEBARRIA MORANT ◽

Vicente URIOS

Keyword(s):

Energy Expenditure ◽

Parental Care ◽

Breeding Season ◽

Video Recording ◽

Experimental Manipulation ◽

Biparental Care ◽

Breeding Ecology ◽

Parental Effort ◽

Ecological Data ◽

Movement Trajectories

Abstract Cutting-edge technologies are extremely useful to develop new workflows in studying ecological data, particularly to understand animal behaviour and movement trajectories at the individual level. Although parental care is a well-studied phenomenon, most studies have been focused on direct observational or video recording data, as well as experimental manipulation. Therefore, what happens out of our sight still remains unknown. Using high-frequency GPS/GSM dataloggers and tri-axial accelerometers we monitored 25 Bonelli’s eagles (Aquila fasciata) during the breeding season to understand parental activities from a broader perspective. We used recursive data, measured as number of visits and residence time, to reveal nest attendance patterns of biparental care with role specialization between sexes. Accelerometry data interpreted as the Overall Dynamic Body Acceleration, a proxy of energy expenditure, showed strong differences in parental effort throughout the breeding season and between sexes. Thereby, males increased substantially their energetic requirements, due to the increased workload, while females spent most of the time on the nest. Furthermore, during critical phases of the breeding season, a low percentage of suitable hunting spots in eagles’ territories led them to increase their ranging behaviour in order to find food, with important consequences in energy consumption and mortality risk. Our results highlight the crucial role of males in raptor species exhibiting biparental care. Finally, we exemplify how biologging technologies are an adequate and objective method to study parental care in raptors as well as to get deeper insight into breeding ecology of birds in general.

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Effects of natural disturbance and selective logging on Nothofagus forests in south-central Chile

Journal of Biogeography ◽

10.1046/j.1365-2699.2002.00734.x ◽

2002 ◽

Vol 29 (7) ◽

pp. 955-970 ◽

Cited By ~ 17

Author(s):

William Pollmann

Keyword(s):

Natural Disturbance ◽

Selective Logging ◽

Central Chile ◽

South Central ◽

Nothofagus Forests

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Breeding Ecology of the Western Long-billed Corella, Cacatua pastinator pastinator

Wildlife Research ◽

10.1071/wr9910091 ◽

1991 ◽

Vol 18 (1) ◽

pp. 91 ◽

Cited By ~ 24

Author(s):

GT Smith

Keyword(s):

Clutch Size ◽

Western Australia ◽

Divorce Rate ◽

Small Population ◽

Breeding Ecology ◽

Pair Bonds ◽

The Mean ◽

Wing Growth ◽

First Time ◽

Older Siblings

The breeding ecology of a small population of the western long-billed corella, Cacatua p. pastinator, was investigated for 6 years in the central wheatbelt of Western Australia. Pair-bonds tended to be long-lasting; however, the divorce rate for birds breeding for the first time was 25% with an overall rate of 15%. Females formed stable pair-bonds by age 2, and bred for the first time between 3 and 5 years old; males started breeding when 5 years old. Clutches (range from one to four, mode three) were started in early August; 78% are started in the last 3 weeks of the month. Mean clutch size, brood size and number fledged were 2.7 , 1.9 and 1.6 respectively; there were no significant differences in these parameters among the six years of the study. Hatching was asynchronous and was followed by the death of the young nestlings when they were significantly smaller (77%) than their older siblings. Nestlings fledged when they were about 60 days old; neither their mass or degree of wing growth influenced fledging age. Mean mass of fledglings from broods of three was significantly greater than that of broods of two or one. Productivity was assessed by the numbers of young fledging, surviving the post-fledging period, and reaching independence. Neither mass nor condition at fledging influenced any of these measures; productivity in all three increased with clutch size. Rainfall and temperature had no influence on the numbers fledged, but the number reaching independence was significantly and positively correlated with the mean maximum summer temperature. The results are discussed in relation to the results from studies of other species of cockatoos living in the wheatbelt of Western Australia.

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Clutch Size, Incubation Period, and Nestling Period of the American Goldfinch

The Auk ◽

10.2307/4083298 ◽

1968 ◽

Vol 85 (3) ◽

pp. 494-498 ◽

Cited By ~ 2

Author(s):

Andrew J. Berger

Keyword(s):

Incubation Period ◽

Clutch Size ◽

Nestling Period

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THE NEST, EGGS, AND NESTLING OF COOPMANS’S ELAENIA ELAENIA BRACHYPTERA (TYRANNIDAE)

Revista Ecuatoriana de Ornitología ◽

10.18272/reo.vi5.1080 ◽

2020 ◽

pp. 40-51

Author(s):

Harold Francis Greeney ◽

Kimberly S. Sheldon

Keyword(s):

Clutch Size ◽

Breeding Ecology ◽

Comprehensive Review ◽

Left Behind ◽

River Floodplains ◽

Nest Placement ◽

Periodic Flooding ◽

First Descriptions

We provide the first descriptions of the nest, eggs, and nestling of Coopmans’s Elaenia Elaenia brachyptera from the foothills of northeastern Ecuador. We describe 7 active nests, 10 eggs, and 1 mid-aged nestling. Nests are open cups, woven of flexible, pale fibers and rootlets, externally decorated with various loosely-arranged materials. They are placed in small saplings within flat, rocky, river floodplains. Nest placement and architecture make nests difficult to distinguish from naturally accumulated materials left behind by periodic flooding. Clutch size ranged from 1–2 eggs and we estimate incubation to last 15–16 days. Eggs are typical of the genus, buffy to creamy white with small cinnamon and lavender spots and blotches concentrated at the larger end. We also provide a comprehensive review of published literature on the nests, eggs, and breeding ecology for the genus Elaenia, including studies on 30 of the 46 currently recognized taxa.

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