Clutch frequency, egg and clutch characteristics, and nesting activity of spur-thighed tortoises, Testudo graeca, in southwestern Spain

1996 ◽  
Vol 74 (3) ◽  
pp. 560-564 ◽  
Author(s):  
C. Diaz-Paniagua ◽  
C. Keller ◽  
A. C. Andreu
Keyword(s):  
Clutch Size ◽  
Carapace Length ◽  
Individual Female ◽  
Testudo Graeca ◽  
Starting Date ◽  
Nesting Activity ◽  
Reproductive Variable ◽  
Nesting Season

Reproduction in female spur-thighed tortoises (Testudo graeca) in a population from southwestern Spain was studied by X-radiography of thread-trailed and radio-tagged individuals. Most females reproduce every year, laying one to four clutches from April to June with internesting intervals ranging from 21 to 29 days. Clutch size varied from 1 to 7 eggs and averaged 3.5 eggs. Carapace length and mass of females were positively correlated with the starting date and duration of the nesting season, while age was not correlated with any reproductive variable. Eggs averaged 33.87 × 27.97 mm in dimensions and 14.4 g in mass. Female mobility increased shortly before or after nesting, which resulted in wide dispersal of the various nests laid by an individual female.

scholarly journals Drought Induced Nepotistic Behaviour in Indian Black Ibis (Pseudibis papillosa) Inhabiting the Arid Zone of Rajasthan, India

Our Nature ◽  
2009 ◽  
Vol 6 (1) ◽  
pp. 47-51
Author(s):  
K.C. Soni ◽  
A.N. Sharma ◽  
V.C. Soni
Keyword(s):  
Clutch Size ◽  
Kin Selection ◽  
Hatching Success ◽  
Arid Zone ◽  
Breeding Birds ◽  
Breeding Female ◽  
Fledgling Success ◽  
Reproductive Activities ◽  
Nesting Activity

Drought induced nepotistic behaviour in the Indian Black ibis (Pseudibis papillosa) inhabiting the arid zone of Rajasthan has been studied. The aim of the present study is to know about any breeding abnormalities induced in the Indian Black ibis by seasonal tragedy like drought. As such the nepotistic behaviour is not found in the Black ibis (Pseudibis papillosa) during normal season. Drought induces a reduced nesting activity and nepotistic behaviour in the Black ibis inhabiting arid zone. The helper birds (Non breeding birds of the own species) become active during drought to assist breeding pairs of Black ibis in various reproductive activities like feeding of breeding female, nestlings, fledglings and defending the nests. The role of helpers in breeding activities of Black ibis during drought also improves their clutch size, hatching success and fledgling success. The significance of the drought induced nepotistic behaviour in Black ibis in view of Hamilton’s theory of kin selection has been discussed.Keywords: Nepotistic behaviour, Black ibis, arid zone, Rajasthan, Indiadoi: 10.3126/on.v6i1.1654Our Nature (2008)6:47-51

Seasonal changes in reproductive output of a year-round nesting population of the green turtle Chelonia mydas at Huyong Island, Thailand

2008 ◽  
Vol 29 (4) ◽  
pp. 559-566
Author(s):  
Tohya Yasuda ◽  
Kongkiat Kittiwattanawong ◽  
Winai Klom-in ◽  
Nobuaki Arai
Keyword(s):  
Reproductive Output ◽  
Environmental Parameters ◽  
Chelonia Mydas ◽  
Green Turtles ◽  
Significant Relationships ◽  
Significant Difference ◽  
Specific Factors ◽  
The Tropics ◽  
Nesting Activity ◽  
Nesting Season

AbstractFor the vast majority of reptiles, low temperature is a major constraint on reproduction. However, continuous reproduction is not always observed even in equatorial climates. In the present study, we examined the reproductive output of green turtles in a year-round nesting population on Huyong Island, Thailand. From 1996 to 2007, 121 females were identified. Because individual turtles nest several times within a season, we defined the nesting season of an individual as the month during which the first nesting activity was detected. We found a significant difference in clutch frequency among months. However, there were no significant relationships during the nesting period between clutch frequency and environmental parameters such as mean daily air temperature, precipitation and maximum wind speed. Although we could not identify the specific factors, our findings suggest that environmental factors may regulate seasonal variation in reproductive output even in the tropics.

Intraspecific nest parasitism in Red-breasted Mergansers

1988 ◽  
Vol 66 (11) ◽  
pp. 2454-2458 ◽  
Author(s):  
Andrew D. Young ◽  
Rodger D. Titman
Keyword(s):  
New Brunswick ◽  
Incubation Period ◽  
Clutch Size ◽  
Embryo Development ◽  
Nest Parasitism ◽  
Mergus Serrator ◽  
Intraspecific Nest Parasitism ◽  
Reproductive Tactic ◽  
Nesting Season

We studied intraspecific nest parasitism in an island nesting population of Red-breasted Mergansers (Mergus serrator) in New Brunswick. Of the nests examined, 64% contained eggs from more than one female. This estimate is probably low because the criteria to detect parasitism were conservative. Parasitized nests were initiated, on average, 3 days earlier than normal nests. Parasitic laying occurred throughout the nesting season. A larger proportion of eggs hatched from normal (89%) than from parasitized (75%) nests because 14% of the eggs in parasitized nests were laid during the host's incubation period and failed to hatch in time. A greater percentage of eggs hatched from parasitized nests during the peak nesting period. Parasitized and normal nests produced the same number of ducklings. There was no difference in the percentage of dead, infertile, and lost eggs from normal compared to parasitized nests. The number of nests containing at least one dead egg increased with clutch size. Most host females accepted parasitic eggs during incubation without deserting. Incubation was prolonged on parasitized nests and on nests with low synchronization of embryo development. Nest parasitism is a common reproductive tactic in at least some female Red-breasted Mergansers.

scholarly journals Nest and Nidification Activities of the Spoonbill Platalea leucorodia in Westerghat Region of Shimoga, Karnataka

Our Nature ◽  
1970 ◽  
Vol 7 (1) ◽  
pp. 26-31
Author(s):  
G.Y. Dayananda ◽  
B.B. Hosetti
Keyword(s):  
Clutch Size ◽  
Site Selection ◽  
Nest Site ◽  
Nest Site Selection ◽  
Nest Size ◽  
Nesting Habitat ◽  
Nesting Material ◽  
Nesting Activity

Nest and nidification behaviour of the Spoonbill, Platlea leucorodia (Family- Threskiornithidae) was studied for three seasons during 2003-2005, at Gudavi Bird Sanctuary (GBS), Gudavi village, Sorab, Karnataka. The GBS harbored about 12 thousand birds of various species, of these, only 10-12 pairs of Spoonbills were breeds every year in this place. There were five Spoonbill nests, of which one was old egret nest and the four were newly built by Spoonbills. The clutch size was two to three in each nest (N = 5) and the shape of the egg was oval, white with small brown spots. The nesting activity usually starts in the month of late July and ends during December. The nesting activity, nest site selection, nesting habitat, nesting material, nest size, and nidification of Platalea leucorodia are discussed in this paper.Key words: Spoonbill, Platalea leucorodia, Nest and Nidification, Gudavi Bird Sanctuary,Shimoga.DOI: 10.3126/on.v7i1.2550Our Nature (2009) 7:26-31 

Optimal egg size in a suboptimal environment: reproductive ecology of female Sonora mud turtles (Kinosternon sonoriense) in central Arizona, USA

2012 ◽  
Vol 33 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Jeffrey E. Lovich ◽  
Sheila V. Madrak ◽  
Charles A. Drost ◽  
Anthony J. Monatesti ◽  
Dennis Casper ◽  
...  
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Carapace Length ◽  
Reproductive Ecology ◽  
X Ray ◽  
Adult Females ◽  
Aperture Width ◽  
Montezuma Well ◽  
Morphological Constraint ◽  
Central Arizona

We studied the reproductive ecology of female Sonora mud turtles (Kinosternon sonoriense) at Montezuma Well, a chemically-challenging natural wetland in central Arizona, USA. Females matured between 115.5 and 125 mm carapace length (CL) and 36-54% produced eggs each year. Eggs were detected in X-radiographs from 23 April-28 September (2007-2008) and the highest proportion (56%) of adult females with eggs occurred in June and July. Clutch frequency was rarely more than once per year. Clutch size was weakly correlated with body size, ranged from 1-8 (mean = 4.96) and did not differ significantly between years. X-ray egg width ranged from 17.8-21.7 mm (mean 19.4 mm) and varied more among clutches than within. Mean X-ray egg width of a clutch did not vary significantly with CL of females, although X-ray pelvic aperture width increased with CL. We observed no evidence of a morphological constraint on egg width. In addition, greater variation in clutch size, relative to egg width, suggests that egg size is optimized in this hydrologically stable but chemically-challenging habitat. We suggest that the diversity of architectures exhibited by the turtle pelvis, and their associated lack of correspondence to taxonomic or behavioral groupings, explains some of the variation observed in egg size of turtles.

Observations of body size, growth, and reproduction in Blanding's turtle (Emydoidea blandingii) from western Nebraska

1992 ◽  
Vol 70 (9) ◽  
pp. 1690-1695 ◽  
Author(s):  
John W. Rowe
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Carapace Length ◽  
Reproductive Output ◽  
Egg Mass ◽  
Mature Adult ◽  
Emydoidea Blandingii ◽  
Size Growth ◽  
Sexually Mature ◽  
Growth And Reproduction

Body size, growth, and reproduction of Emydoidea blandingii from several localities in western Nebraska were investigated. Female carapace length averaged 209.2 mm (214.8 mm for those known to be sexually mature). Adult male carapace length averaged 200.8 mm and was not significantly different from that of females, but males had pigmented tomia. Covariance analysis using carapace length as a covariate revealed that females had a significantly longer plastron and higher shell than males. Turtles showed a 70.1% increase in length of the left abdominal scute during the 1st year. Growth declined rapidly and became more constant about the 4th year (about 4–9% per year). Clutch size averaged 14.9, clutch wet mass averaged 168.5 g, and egg wet mass averaged 11.82 g. No measure of reproductive output (i.e., clutch size, clutch wet mass, relative clutch mass) or egg size (relative egg mass, egg wet mass, egg length, or egg width) was significantly correlated with maternal carapace length. Comparisons with other populations of E. blandingii are made.

Green turtle (Chelonia mydas) nesting on Atol das Rocas, north-eastern Brazil, 1990–2008

2012 ◽  
Vol 93 (4) ◽  
pp. 1117-1132 ◽  
Author(s):  
Claudio Bellini ◽  
Armando J.B. Santos ◽  
Alice Grossman ◽  
Maria A. Marcovaldi ◽  
Paulo C. R. Barata
Keyword(s):  
Green Turtle ◽  
Carapace Length ◽  
Temporal Distribution ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Annual Number ◽  
Eastern Brazil ◽  
North Eastern ◽  
The Mean ◽  
Nesting Activity

In this paper, information is presented on green turtle (Chelonia mydas) nesting on Atol das Rocas (Rocas Atoll), north-eastern Brazil. The temporal distribution of nesting events per season, annual number of nests, carapace length of nesting females, clutch size, hatching success, incubation period, internesting interval, clutch frequency, observed reproductive lifespan, and remigration period are reported. The study period included the nesting seasons from 1990 to 2008, but no regular beach monitoring was carried out in 1998 and 1999. Two sorts of methods were applied to the estimation of the annual number of nests in some seasons. Taking into account the estimated annual numbers of nests, the mean annual number of nests in the study period, excluding 1998–1999, was 335 (standard deviation = 139, range = 136–563, N = 17). An analysis of the available data indicates that the average nesting levels at the beginning of the study period (the first five seasons) and at its end (the last five seasons) were roughly the same. The mean curved carapace length of the nesting turtles decreased significantly during the study period, from 115.9 cm in 1990–1992 to 112.9 cm in 2006–2008. Atol das Rocas was established as a federal biological reserve in 1979, but regular sea turtle conservation activities actually started there in 1990. Since that year, the killing of nesting turtles has ceased, nesting activity by the turtles can proceed in an undisturbed fashion, and their clutches can incubate in a protected environment.

Reproductive patterns of the hawksbill turtle Eretmochelys imbricata in sandy beaches of the Yucatan Peninsula

2007 ◽  
Vol 87 (3) ◽  
pp. 815-824 ◽  
Author(s):  
Roberto Pérez-Castañeda ◽  
Alberto Salum-Fares ◽  
Omar Defeo
Keyword(s):  
Clutch Size ◽  
Yucatan Peninsula ◽  
Sandy Beaches ◽  
Main Peak ◽  
Eretmochelys Imbricata ◽  
Yucatán Peninsula ◽  
Emergence Success ◽  
Important Region ◽  
Long Term Trends ◽  
Nesting Activity

Daily censuses of the hawksbill turtle Eretmochelys imbricata were taken during the nesting seasons 1995–2001 in three sandy beaches of the Yucatan Peninsula, Mexico (Celestun, El Cuyo and Isla Holbox), to evaluate aspects of its reproductive biology. A total of 9059 hawksbill turtle clutches was estimated for the study period. Nesting seasons began in mid-April and ended in early September, peaking in May–June. No significant differences were detected in the mean number of clutches per km among beaches. The largest number of clutches was observed in the supralittoral zone (6341: 70%), followed by the dune (2491: 27.5%) and the intertidal (227: 2.5%) zones. Variation in number of clutches showed a main peak in 1999, decreasing in 2000 and 2001. A significant decrease (3 cm) in body size of nesting females was detected between 1995 and 2001. Mean clutch size was 140 eggs/clutch, and a significant positive relationship between curved carapace length and mean clutch size was found at the three beaches. Incubation period, hatching success and emergence success varied between years (lowest values in 1998) and beaches (highest values at Isla Holbox), with no significant differences between the supralittoral and dune zones. Even though there was no evidence of a decreasing trend in nesting activity for the study period, the decrease in 2000–2001 suggests that additional beach monitoring is necessary to identify long-term trends, and to reduce potential losses of nests by human and natural causes in this globally important region for the hawksbill turtle.

NEsting by the hawsbill turtle (Eretmochelys imbricata) on Milman Island, Great Barrier Reef, Australia

1995 ◽  
Vol 22 (2) ◽  
pp. 241 ◽  
Author(s):  
KA Loop ◽  
JD Miller ◽  
CJ Limpus
Keyword(s):  
Clutch Size ◽  
Carapace Length ◽  
Average Diameter ◽  
Average Weight ◽  
Nesting Biology ◽  
Eretmochelys Imbricata ◽  
Nest Sites ◽  
Emergence Success ◽  
Incubation Temperatures ◽  
Hawksbill Turtles

Nesting biology of hawksbill sea turtles (Eretmochelys imbricata) is described with morphometric and meristic measurements collected from 365 turtles over 76 nights of beach patrols on Milman I. The nesting season was already in progress when the study began in January and continued after the research team left in March 1991. Average renesting interval was 14.2 days, and the hawksbill turtles laid an average of 2.6 clutches during the study period. Nest sites were located most commonly under trees (67.2%). Average curved carapace length was 81.7 cm, width was 70.6 cm, and weight after laying was 50.3 kg. Mean clutch size was 124 eggs. Eggs had an average diameter of 3.48 cm and an average weight of 25.7 g. Emergence success rate was 79.9% for hawksbill hatchlings, which had an average straight carapace length of 3.96 cm and weight of 13.3 g. Incubation temperatures were monitored and sex ratios determined in four clutches, two in shaded and two in unshaded sand. The sexes of 25 hatchlings from each clutch were identified. Two unshaded clutches produced 92% and 100% female hatchlings while two shaded clutches produced 64% and 44% female hatchlings. Statistical differences were not found between the presented hawksbill turtle curved carapace length, weight after laying and clutch size and those collected elsewhere in Queensland by earlier studies.

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