Ecogeographic and Temporal Variation in the Eggs and Nests of the Peregrine, Falco peregrinus, (Aves : Falconidae) in Australia

1982 ◽  
Vol 9 (2) ◽  
pp. 277 ◽  
Author(s):  
P Olsen
Keyword(s):  
Land Use ◽  
Egg Size ◽  
Prey Species ◽  
Egg Laying ◽  
Peregrine Falcon ◽  
Falco Peregrinus ◽  
Hollow Trees ◽  
Eastern Australia ◽  
The Mean ◽  
Tree Hollow

Latitudinal and temperature-related clines in egg size were found for the peregrine falcon, Falco peregrinus, in Australia, egg size increasing with increasing latitude and decreasing temperature. The breakdown of these clines since the 1940s corresponded temporally with the introduction of DDT to agriculture and with greater intensification of land use. In eggs collected since the 1940s, the clines were still present north of 33�S. and in areas where the mean maximum September temperature was e21�C, but not south of 34�S. and in areas of mean maximum September temperature < 21�C. Mean clutch size was 2.9 (range 1-5); without evidence of clines. Most eggs were collected in September in south-eastern Australia. The timing of the egg-laying period was correlated with latitude and temperature, corresponding to the seasonal influx of migrant prey species and the breeding season of major prey species. The geographical distribution of cliff nests, stick nests and tree-hollow nests is discussed; the use of hollow trees appears to be restricted geographically. Eggs from some tree-hollow nests were larger than those from other types of nest.

scholarly journals Peregrine Falcon Eggs: Egg Size, Hatchling Sex, and Clutch Sex Ratios

The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 327-335 ◽  
Author(s):  
William Burnham ◽  
Calvin Sandfort ◽  
James R. Belthoff
Keyword(s):  
New Mexico ◽  
Egg Size ◽  
Resource Competition ◽  
Sex Ratios ◽  
Peregrine Falcon ◽  
Falco Peregrinus ◽  
Local Resource Competition ◽  
Local Resource ◽  
Peregrine Falcons ◽  
Falco Peregrinus Anatum

AbstractEggs (n = 367) collected from wild Peregrine Falcon (Falco peregrinus anatum) nests between 1976 and 1990 in Colorado and New Mexico were artificially incubated and hatched. We retrospectively examined these data for variation in egg length, breadth, and initial mass of hatchlings to resolve questions about relationships among egg size, chick size, and sex; and egg size related to first and second clutches and years. Egg length and breadth were significantly related to chick mass at hatching. Neither egg size nor hatchling mass were related to sex. Egg breadth slightly increased and then decreased over the years eggs were collected, which possibly reflects a re-established and then aging wild falcon population or other environmental variation. We also evaluated clutch sex ratios relative to theory based on sexual size dimorphism and local resource competition. Sex ratios did not significantly differ from 1:1 within first or second clutches separately or when combined. Thus, Peregrine Falcons in this population apparently did not skew clutch sex ratios in accordance with local resource competition or Fisherian theory.Huevos de Halcones Peregrinos: Tamaño, Sexo de los Pichones y Proporción de Sexos en la NidadaResumen. Huevos (n = 367) colectados de nidos silvestres de halcones peregrinos (Falco peregrinus anatum) entre 1976 y 1990 en Colorado y New Mexico fueron incubados artificialmente hasta eclosionar. Examinamos esos datos retrospectivamente en cuanto a la variación en la longitud y ancho del huevo y el peso inicial de los pichones para contestar preguntas sobre las relaciones entre tamaño del huevo, tamaño del pichón y sexo, y entre el tamaño del huevo con relación a primeras y segundas nidadas y años. La longitud y el ancho del huevo estuvieron significativamente relacionados con la masa del pichón al eclosionar. El tamaño del huevo y el peso del pichón no estuvieron relacionados con el sexo. El ancho de los huevos aumentó ligeramente y luego disminuyó a través de los años en que los huevos se colectaron, lo que posiblemente refleja una población silvestre de halcones re-establecida y posteriormente senescente, u otro tipo de variación ambiental. También evaluamos la proporción de sexos en las nidadas con relación a la teoría basada en el dimorfismo sexual de tamaño y la competencia local por recursos. Las proporciones de sexos no difirieron significativamente de 1:1 entre primeras o segundas nidadas separadamente o de forma combinada. Por tanto, los halcones peregrinos en esta población aparentemente no sesgaron la proporción de sexos en sus nidadas de acuerdo a la competencia local por recursos o a la teoría Fisheriana.

scholarly journals [The decline of one of the most threatened European birds of prey: 41 years of observations on the Lanner, Falco biarmicus in Sicily]

2020 ◽  
Vol 89 (2) ◽  
Author(s):  
Giovanni Salvo
Keyword(s):  
Interspecific Competition ◽  
Sea Level ◽  
Small Mammals ◽  
Breeding Success ◽  
Egg Laying ◽  
Birds Of Prey ◽  
Peregrine Falcon ◽  
Falco Peregrinus ◽  
Bonelli’S Eagle ◽  
Hieraaetus Fasciatus

[The results of a research on Lanner in southern Sicily, carried out between 1978 and 2018, are reported. 32 Lanner nesting territories have been taken into account, from sea level up to 1200 m of altitude. Until 2005, there were about 25 nesting pairs in the area; but in the following years there was a steady decline. At least 16 sites have been gradually abandoned because of human persecution and, at a lesser degree, of the interference with the Peregrine falcon, Falco peregrinus, and the Bonelli’s eagle, Hieraaetus fasciatus. At present, the number of Lanner pairs breeding in the study area is around 12. From 120 nesting attempts followed, 216 youngs fledged, with a productivity of 1.80, with breeding success of 1.98, fledging rate of 2.40. Out of 109 nests in which there was egg laying, 90 were successful. Out of successful nests, 11 fledged 1 young (12.2%); 37 nests 2 youngs (41.1 %); 37 nests, 3 youngs (41.1%); 5 nests, 4 youngs (5.6%). The number of pairs that have laid eggs, in relation to the number of the monitored nests, was of 90.8%. The ratio between the number of nests in which youngs were raised and the number of pairs that laid their eggs was 88.1%. The ratio between the number of nests from which youngs fledged and the number of breeding pairs was 93.7%.The number of successfully breeding nests, in relation to the number of monitored nests, was 75%. As regards the diet, birds represent Lanner’s most frequent preys. Out of the 415 preys identified, 383 (92.3%) are made up of birds, 29 (7%) by small mammals, 3 (0.7%) by reptiles. In addition to human persecution, the population of Lanner in Sicily is influenced by interspecific competition, particularly with the Peregrine falcon; but in 2 cliffs, about 1 km long and with a substantial wealth of prey, both falcons have been successfully reproducing for over 10 years]. [Article in Italian]  

Fecundity, egg size and the influence of rainfall in an isolated population of malleefowl (Leipoa ocellata)

2005 ◽  
Vol 32 (7) ◽  
pp. 639 ◽  
Author(s):  
David Priddel ◽  
Robert Wheeler
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
New South ◽  
Extended Period ◽  
Early Summer ◽  
Egg Laying ◽  
Daily Maximum ◽  
Isolated Population ◽  
South Wales ◽  
The Mean

An isolated population of malleefowl (Leipoa ocellata) at Yalgogrin in New South Wales, Australia, was studied intensively between 1986–87 and 1998–99. During this period the population produced 124 clutches, comprising a total of 1705 eggs. The number of clutches per annum varied between 5 and 15. Eggs were laid between mid-August and mid-February, with 90% laid between the last week of September and the first week of January. The mean date of laying of the first egg of each clutch (±s.d.) was 21 September ± 13 days and the mean date of the last egg was 23 December ± 19 days. The mean duration of egg laying varied significantly between years (range 70–117 days) and was negatively correlated with the daily maximum ambient temperature in December. Cool temperatures and rain in early summer prolonged the laying season. The mean interval between laying was 6.4 ± 1.1 days (range 3–12 days), with eggs laid at a faster rate during the first half of the laying period. Overall, mean clutch size was 14.1 ± 5.8 (range 1–28). Large clutches were the result of an extended period of laying rather than an increase in the rate of laying. Mean clutch size was greatest when laying extended into mid-February. The best predictor of clutch size was rainfall between May and December – the interval spanning both nest construction and egg laying. The mean volume of all measured eggs (n = 1362) was 162.1 ± 9.0 mL (range 99–200 mL). Egg volume varied during the laying period, with those eggs laid early or late in the breeding season being smaller. Eggs at Yalgogrin were, on average, 10.5% smaller than those recorded at nearby Pulletop.

Retrobulbar rhabdomyosarcoma in a neotropical peregrine falcon (Falco peregrinus cassini)

2013 ◽  
Vol 17 (1) ◽  
pp. 73-75 ◽  
Author(s):  
Michelle J. Freundt Coello ◽  
Lee S. Schaeffer
Keyword(s):  
Peregrine Falcon ◽  
Falco Peregrinus

The influence of nutrition on egg-production and longevity in unmated female body-lice (Pediculus humanus corporis: Anoplura)

Parasitology ◽  
1941 ◽  
Vol 33 (1) ◽  
pp. 40-46 ◽  
Author(s):  
A. J. Haddow
Keyword(s):  
Female Body ◽  
Egg Production ◽  
Egg Laying ◽  
The Body ◽  
Unmated Female ◽  
Pediculus Humanus ◽  
The Third ◽  
Significant Difference ◽  
The Mean ◽  
Body Lice

1. Isolated unmated female body-lice were worn in pillboxes between the skin and the clothes. They were kept constantly on the body but, by a simple device, groups of ten were permitted feeding periods of different length. These groups were fed for 4, 8, 12, 16, 20 and 24 hr. per day respectively. Another group of ten were never allowed to feed after the last moult.2. Some of the figures for egg yield were high. Lice in the 24 hr. group were able to maintain a rate of ten eggs per day for 4−5 days at a time.3. No significant difference in longevity or rate of egg-laying was found to exist between the 12, 16, 20 and 24 hr. groups nor between the 4 and 8 hr. groups but a pronounced and significant difference exists between the 8 and 12 hr. groups. Below 12 hr. there is a sharp fall in longevity and rate of egg production. The unfed group all died, without laying, on the third day.4. The rate of laying as shown by the mode increases progressively with increase in time allowed daily for feeding.5. With regard to the mean eggs per louse the position is less clear. It is felt that the 24 hr. group may differ significantly from the 12, 16 and 20 hr. groups but this is uncertain.

scholarly journals Effect on nitrate concentration in stream water of agricultural practices in small catchments in Brittany: I. Annual nitrogen budgets

2002 ◽  
Vol 6 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
P. Durand ◽  
C. Martin ◽  
F. Vertès ◽  
...  
Keyword(s):  
Land Use ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Agricultural Practices ◽  
Climatic Conditions ◽  
Nitrogen Budgets ◽  
Annual Variations ◽  
Nitrate Concentrations ◽  
The Mean ◽  
Small Catchments

Abstract. The hydrological and biogeochemical monitoring of catchments has become a common approach for studying the effect of the evolution of agricultural practices on water resources. In numerous studies, the catchment is used as a "mega-lysimeter" to calculate annual input-output budgets. However, the literature reflects two opposite interpretations of the trends of nitrate concentration in streamwater. For some authors, essentially in applied studies, the mean residence time of leached nitrate in shallow groundwater systems is much less than one year and river loads reflect annual land use while for others, nitrate is essentially transport limited, independent of soil nitrate supply in the short term and annual variations reflect changes in climatic conditions. This study tests the effect of agricultural land-use changes on inter-annual nitrate trends on stream water of six small adjacent catchments from 0.10 to 0.57 km2 in area, on granite bedrock, at Kerbernez, in Western Brittany (France). Nitrate concentrations and loads in streamwater have been monitored for nine years (1992 to 2000) at the outlet of the catchments. An extensive survey of agricultural practices from 1993 to 1999 allowed assessment of the nitrogen available for leaching through nitrogen budgets. For such small catchments, year-to-year variations of nitrate leaching can be very important, even when considering the 'memory effect' of soil, while nitrate concentrations in streamwater appear relatively steady. No correlation was found between the calculated mean nitrate concentration of drainage water and the mean annual concentration in streams, which can even exhibit opposite trends in inter-annual variations. The climatic conditions do not affect the mean concentration in streamwater significantly. These results suggest that groundwater plays an important role in the control of streamwater nitrate concentration. Keywords: nitrate, diffuse pollution, agricultural catchment, nitrogen budget, leaching, Kerbernez catchments

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