Hummingbird eggs and babies are a favourite snack for nest-robbing jays, so what’s a mother to do to protect her family? According to a new study, it’s best to build her nest near or under a hawk nest
Wednesday 30 September 2015 09.09 BST
Last modified on Thursday 1 October 201507.42 BST
Tiny hummingbird eggs and babies are a favourite snack for nest-robbing jays, so what’s a mother hummingbird to do to protect her family? According to a study published recently in the journal, Science Advances, the hummingbird cleverly builds her nest near or under a hawk nest. The reason for this seemingly risky behaviour? When hawks are nesting nearby, jays forage higher above the ground to avoid being attacked from above by the hungry hawk parents. This elevation in the jays’ foraging height creates a cone-shaped jay-free safe area under the hawk nests where mother hummingbirds, their babies and nests, dramatically increased survival rates.
Predator-prey relationships are subtle and multi-faceted. For example, predators at one level in a food web are often are prey at the next level. The position in a food web or food chain that an organism occupies is referred to as its trophic level. Predictably, prey animals tend to avoid their predators, even when doing so restricts the prey species’ access to valuable resources, such as food, water or habitat (doi:10.1007/s10531-008-9324-5). Thus, the presence of just a few top predators has numerous effects – direct and indirect – that cascade down the trophic levels within an ecosystem. This is known as a trophic cascade.
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