Information centre hypothesis
[1] They stated that birds join assemblages in order to gain information about food resources and increase foraging efficiency.
[1] The hypothesis has been studied and experimentally supported in many different types of communally roosting birds, notably crows and vultures.
This strategy is regarded as evolutionarily adaptive, because it would prevent the unsuccessful bird from having to start the search for food over in a random method.
[1] By the early 1980s, the information centre hypothesis was widely accepted and used to explain communal roosting behaviour, however this popularity also led to substantial criticism.
[2] While it may seem counterproductive for a successful individual to share resource knowledge, the information centre hypothesis argues that this behaviour is adaptive.
[4] In addition, multiple studies have made note that food sources for flock-living birds are typically consumed quickly by other predators, such as mammals or decomposers.
Red-winged blackbirds (Agelaius phoeniceus) exhibit synchronized breeding patterns, as well as have displays to attract birds to join the same nesting site.
An observation Ward and Zahavi had done of red-billed queleas and the cattle egrets showed altered behavior after individually failing to find food in the morning and later in the afternoon.
Hooded crows exhibit communal roosting behaviour and often feed in flocks, making them a good candidate species for studies of the information centre hypothesis.
[6] A study conducted by Sonerud, Smedshaug, and Brathen (2001) examined the roost and feeding behaviours of 34 hooded crows over three years, with results supporting the information centre hypothesis.
[6] This is supported when compared to the naive individuals who did not roost overnight with the leader, and had significantly lower levels of finding the food source on Day 2.
[5] In a study by Harel et al. (2017), movements and behaviour of approximately 200 Eurasian griffon vultures were recorded over a five-year period.
[4][10] A further criticism states that the information centre hypothesis is not valid because it does not represent an evolutionarily stable strategy (ESS).
[4] According to Heinz Richner and Philipp Heeb (1995), the primary issue with the information centre hypothesis is the concept that a successful forager would return to the roost to help other, unsuccessful individuals.
[10] They argue that this issue cannot be solved without making assumptions regarding kin benefits, and thus the hypothesis cannot be confirmed to be true.
[4] A review paper by Bijleveld et al. (2009) suggests that broadening the hypothesis to include these other information sharing possibilities better explains the phenomenon of communal roosting.
[4] For example, Ward and Zahavi argued that a dramatic aerial display by a bird was an advertisement to others regarding their knowledge of a food source.
