Search results
Results From The WOW.Com Content Network
Female birds are able to produce more of a certain gender of birds that are more likely to survive under extreme conditions. In birds, the females' egg determines the gender of the offspring, not the male's sperm. In zebra finches, a study showed the effect of food on gender ratio production. For females, egg production is a metabolically ...
Some birds and some lizards follow this pattern. Type III or concave curves have the greatest mortality (lowest age-specific survival) early in life, with relatively low rates of death (high probability of survival) for those surviving this bottleneck. This type of curve is characteristic of species that produce a large number of offspring ...
Mortality on breeding grounds: small, insect eating birds contribute to the majority of post-arrival deaths, but many other birds including waders and waterfowls are also distressed by weather changes on breeding grounds. Since young birds are inexperienced, they are more vulnerable than adults to extreme weather conditions. [1] Mortality on ...
Wildlife experts in at least six states are investigating the cause of the bird deaths. Birds acting blind when approached, dying by hundreds. Scientists don't know why.
Due to the increasing human use of coastal waters, Parish envisioned a program that could provide data on both resident and migrant species of birds; mortality rates after oil spills; levels of chronic oiling, information regarding some incidents of entanglement with fishing gear; and causes of death for seabird populations. Since a live bird ...
An Alaska seabird species faced the worst mortality event in modern history, and the population isn’t recovering, a study finds. Experts discuss the future implications.
Mourning doves are prolific breeders. In warmer areas, these birds may raise up to six broods in a season. [33] This fast breeding is essential because mortality is high. Each year, mortality can reach 58% a year for adults and 69% for the young. [38] The mourning dove is generally monogamous and forms strong pair bonds. [38]
Cooperative breeding occurs across taxonomic groups including birds, [5] mammals, [6] fish, [7] and insects. [8] Costs for helpers include a fitness reduction, increased territory defense, offspring guarding and an increased cost of growth. Benefits for helpers include a reduced chance of predation, increased foraging time, territory ...