Allofeeding and parental care Aptenodytes patagonicus Emperor penguin (Aptenodytes patagonicus) feeding its offspring A parent feeding a non-biological chick via bill-to-bill interactions is a form of allofeeding. Parental allofeeding occurs in all altricial species of birds to ensure proper growth, development, and to prevent starvation of their offspring.  This form of allofeeding has been shown to be a form of parental care in some species, such as in king penguins (A. patagonicus). King penguins are pelagic seabirds. King penguin chicks form dense groups called crèches during winter for social thermoregulation when food availability is low. The formation of crèches results from the parents interchangeably leaving starving chicks to gather food from the sea. A study by Lecomte et al., 2015 examined the allofeeding behaviour in king penguins, in which they marked the white underbellies of 74 non-breeding adults and 103 breeding pairs with a unique dark colouring called dye-mark code of Nyanzol-D. Lecomte et al. (2015) found 22\% of the marked adults feed 65\% of the chicks in crèches, revealing that allofeeding behaviour was most common during the breeding season. Lecomte et al. (2015) also identified that most of the 22\% of adult king penguins demonstrating allofeeding behaviour were unable to successfully breed along with few breeders performing the behaviour. The allofeeding behaviour resulted in more feedings for chicks, which is consistent with study by Pierre et al. (1994) that showed that allofeeding in penguins increases the chick growth rate from 35g/day to 190g/day. From these results, Lecomte et al. (2015) concluded that allofeeding increased the survival rate of chicks in crèches. The results imply that parental allofeeding in king penguins is an altruistic behaviour, where allofeeding benefits the young at a cost to the non-biological parent. Notably, no direct benefits to the non-biological parents have been described. The cost of allofeeding non-biological chicks resulted in no detrimental effects to the fitness of the alloparent, because the cost of allofeeding is low (several grams) when compared to the nutritional costs of an adult king penguin, which is several kilograms. However, it is suggested that allofeeding many chicks may cost each chick lost meals that can cause negative effects on the fitness of allofed chicks. In addition, allofeeding decreases when non-biological parents had offspring. Peer allofeeding upright=1.2|House sparrow feeding behaviour There have been many reported cases of allofeeding between siblings in several species of birds. Turdoides sqamiceps For example, the Arabian babblers (T. sqamiceps) are a territorial, desert-inhabiting species of bird that participate in cooperative breeding. In this species, non-breeders show numerous types of cooperative behaviour, including allofeeding. Adult and immature babblers, as well as previous and newly fledged babblers, will frequently engage in allofeeding behaviour.
Allofeeding and parental care A parent feeding a non-biological chick via bill-to-bill interactions is a form of allofeeding. Parental allofeeding occurs in all altricial species of birds to ensure proper growth, development, and to prevent starvation of their offspring. Aptenodytes patagonicus Emperor penguin (Aptenodytes patagonicus) feeding its offspring upright=1.2|Female house sparrow feeding young This form of allofeeding has been shown to be a form of parental care in some species, such as in king penguins (A. patagonicus). King penguins are pelagic seabirds. King penguin chicks form dense groups called crèches during winter for social thermoregulation when food availability is low. The formation of crèches results from the parents interchangeably leaving starving chicks to gather food from the sea. A study by Lecomte et al., 2015 examined the allofeeding behaviour in king penguins, in which they marked the white underbellies of 74 non-breeding adults and 103 breeding pairs with a unique dark colouring called dye-mark code of Nyanzol-D. Lecomte et al. (2015) found 22\% of the marked adults feed 65\% of the chicks in crèches, revealing that allofeeding behaviour was most common during the breeding season. Lecomte et al. (2015) also identified that most of the 22\% of adult king penguins demonstrating allofeeding behaviour were unable to successfully breed along with few breeders performing the behaviour. The allofeeding behaviour resulted in more feedings for chicks, which is consistent with study by Pierre et al. (1994) that showed that allofeeding in penguins increases the chick growth rate from 35g/day to 190g/day. From these results, Lecomte et al. (2015) concluded that allofeeding increased the survival rate of chicks in crèches. The results imply that parental allofeeding in king penguins is an altruistic behaviour, where allofeeding benefits the young at a cost to the non-biological parent. Notably, no direct benefits to the non-biological parents have been described. The cost of allofeeding non-biological chicks resulted in no detrimental effects to the fitness of the alloparent, because the cost of allofeeding is low (several grams) when compared to the nutritional costs of an adult king penguin, which is several kilograms. However, it is suggested that allofeeding many chicks may cost each chick lost meals that can cause negative effects on the fitness of allofed chicks. In addition, allofeeding decreases when non-biological parents had offspring. Peer allofeeding There have been many reported cases of allofeeding between siblings in several species of birds. Turdoides sqamiceps For example, the Arabian babblers (T. sqamiceps) are a territorial, desert-inhabiting species of bird that participate in cooperative breeding. In this species, non-breeders show numerous types of cooperative behaviour, including allofeeding. Adult and immature babblers, as well as previous and newly fledged babblers, will frequently engage in allofeeding behaviour.
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Aptenodytes patagonicus Emperor penguin (Aptenodytes patagonicus) feeding its offspring
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Aptenodytes patagonicus Emperor penguin (Aptenodytes patagonicus) feeding its offspring upright=1.2|Female house sparrow feeding young
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upright=1.2|House sparrow feeding behaviour