Sibling competition in the broods of Little Egrets Egretta garzetta in a southern Tunisian breeding colony

Ostrich ◽  
2020 ◽  
Vol 91 (4) ◽  
pp. 299-304
Author(s):  
Amel Neb ◽  
Slaheddine Selmi
2020 ◽  
Author(s):  
Josep del Hoyo ◽  
Albert Martínez-Vilalta ◽  
Anna Motis ◽  
Nigel Collar ◽  
Guy M. Kirwan ◽  
...  

2020 ◽  
Vol 43 (4) ◽  
pp. 903-919 ◽  
Author(s):  
Si Shen ◽  
Xiao‐Gui Liang ◽  
Li Zhang ◽  
Xue Zhao ◽  
Yun‐Peng Liu ◽  
...  

2001 ◽  
Vol 35 (2) ◽  
pp. 140-146 ◽  
Author(s):  
R. H. Foote ◽  
E. Hare

Rabbit seminal plasma catalase is much higher than in the semen of other mammals, and differences appear to be inherited. Because of the scarcity of information on rabbit blood catalase and haematocrit in Dutch-belted rabbits, an investigation of possible effects of gender, age and genetics on these variables was undertaken. There were 191 rabbits sampled at 2-3 months, 130 at 12 months and 61 at 18-24 months of age. There was no age effect on the haematocrit values and on blood catalase activity. At 12 months of age males had an average haematocrit value of 44% compared with 40% for females ( P < 0.05). Corresponding average catalase values were 431 and 356 units/ml of blood ( P < 0.05). Also catalase was measured in the semen and blood of 34 males, and males differed in both their blood and semen catalase activity ( P < 0.05). The correlation between the two traits was r = 0.44. Heritability ( h2) estimates, based on 231 rabbits were 0.40 for blood catalase activity, and 0.26 for haematocrit. The genetic correlation between the two variables was 0.83 ( P < 0.05). These studies are consistent with the literature in that female rabbits have a slightly lower haematocrit value than males, and this is associated with a lower catalase activity. This appears to be the first report of a study that compares rabbit blood catalase in males and females of different ages. Preliminary evidence that differences may have a heritable basis is consistent with previous studies on rabbit semen catalase.


2021 ◽  
Author(s):  
David A. Ehlers Smith ◽  
Brent Coverdale ◽  
Ben Hoffman ◽  
Christopher Kelly ◽  
Yvette C. Ehlers Smith ◽  
...  

1972 ◽  
Vol 1 (1) ◽  
pp. 3-28 ◽  
Author(s):  
G. Van Wagenen

2016 ◽  
Vol 27 (1) ◽  
pp. 140-152 ◽  
Author(s):  
DANA G. SCHABO ◽  
SONJA HEUNER ◽  
MICHAEL V. NEETHLING ◽  
SASCHA RÖSNER ◽  
ROGER UYS ◽  
...  

SummaryThe number of vultures is declining in many parts of the world due to numerous threats, such as poisoning and collisions with power-lines as well as the lack of adequate food sources. Vulture restaurants, i.e. supplementary feeding stations, have become a widespread conservation tool aimed at supporting vulture colonies. However, it is poorly understood how vulture restaurants influence population dynamics and whether they affect breeding success of vulture populations. We used a 12-year dataset from a breeding colony of the Cape Vulture Gyps coprotheres and a nearby vulture restaurant in South Africa to investigate the effect of supplementary food on population dynamics and breeding success. We found a significantly positive effect of supplementary food during the nest-building stage on the number of breeding pairs. However, breeding success, i.e. the proportion of successful nests, did not depend on supplementary food during the incubation and rearing stage. Especially during the critical rearing stage, the amount of food supplied might not have been sufficient to meet food demands of the colony. Still, our results indicate that carefully managed vulture restaurants might stabilise vulture colonies and can therefore aid vulture conservation.


2010 ◽  
Vol 139 (2) ◽  
pp. 362-381 ◽  
Author(s):  
Christina J. Maranto ◽  
Thomas P. Good ◽  
Francis K. Wiese ◽  
Julia K. Parrish

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