Names of Cuckoo and Cuckoo Chick in Russian Folk Linguistics

The research is carried out in the context of ethnolinguistics, which is aimed at analyzing nominations of ecosystem objects as means of presenting relations between language and culture, and in particular, specificity in their perception by various ethnical and subethnical (dialect) groups. The authors rely on two suppositions: though flora and fauna are reflected diacritically in linguistic consciousness of various dialect communities due to physical, geographical, social environment, there exist some universal lexical and phraseological language means to describe every object of nature. The purpose of the article is to determine the regularities in nomination of the cuckoo as a significant linguocultural representative of fauna. The material for the study was the card file of the Linguistic Atlas of Russian folk dialects, stored at the Institute for linguistic research of the Russian Academy of Sciences (Saint Petersburg). The research has shown that the nominations of the cuckoo and the cuckoo chick have special implications in the linguistic consciousness of the Russian people. These units have onomatopoietic origin, they have undergone phonetic, derivational and semantic transformations in the Russian dialect continuum. Ornithonyms implement a binary semantic correlation, linking the sphere of living nature, to which they belong by denotative features, and the human character – the area where their development of connotative-contextual semantics leads, due to the specifics of the linguocreative thinking of the language personality.

True recognition of nestlings by hosts selects for mimetic cuckoo chicks

Brood parasitic cuckoos lay their eggs in other birds' nests, whereafter the young cuckoo hatches, ejects its nest-mates and monopolizes the care of the host parents. Theory predicts that hosts should not evolve to recognize and reject cuckoo chicks via imprinting because of the risk of mistakenly imprinting on a cuckoo chick in their first brood and thereafter always rejecting their own chicks. However, recent studies have revealed that some hosts do reject cuckoo chicks from the nest, indicating that these hosts’ recognition systems either do not rely on first brood imprinting, or use cues that are independent of chick phenotype. Here, we investigate the proximate mechanisms of chick rejection behaviour in the large-billed gerygone ( Gerygone magnirostris ), a host of the little bronze-cuckoo ( Chalcites minutillus ). We find that gerygones use true template-based recognition based on at least one visual chick trait (the number of hatchling down-feathers), and that this is further mediated by experience of adult cuckoos at the nest during egg-laying. Given the theoretical constraints of acquiring recognition templates via imprinting, gerygones must possess a template of own-chick appearance that is largely innate. This true recognition has facilitated the evolution of very rapid hatchling rejection and, in turn, striking visual mimicry of host young by little bronze-cuckoo chicks.

Cuckoo chicks evicting their nest mates: coincidental observations by Edward Jenner in England and Antoine Joseph Lottinger in France

For centuries, naturalists were aware that soon after hatching the common cuckoo (Cuculus canorus) chick became the sole occupant of the fosterer's nest. Most naturalists thought the adult cuckoo returned to the nest and removed or ate the fosterer's eggs and young, or the cuckoo chick crowded its nest mates out of the nest. Edward Jenner published the first description of cuckoo chicks evicting eggs and young over the side of the nest. Jenner's observations, made in England in 1786 and 1787, were published by the Royal Society of London in 1788. Four years before Jenner's observations, in 1782, Antoine Joseph Lottinger recorded eviction behaviour in France and published his observations in Histoire du coucou d'Europe, in 1795. The importance of Lottinger's and Jenner's observations is considered together.

Sexually antagonistic chromosomal cuckoos

The two kinds of sex chromosomes in the heterogametic parent are transmitted to offspring with different sexes, causing opposite-sex siblings to be completely unrelated for genes located on these chromosomes. Just as the nest-parasitic cuckoo chick is selected to harm its unrelated nest-mates in order to garner more shared resources, sibling competition causes the sex chromosomes to be selected to harm siblings that do not carry them. Here we quantify and contrast this selection on the X and Y, or Z and W, sex chromosomes. We also develop a hypothesis for how this selection can contribute to the decay of the non-recombining sex chromosome.

Experimental evidence for chick discrimination without recognition in a brood parasite host

Recognition is considered a critical basis for discriminatory behaviours in animals. Theoretically, recognition and discrimination of parasitic chicks are not predicted to evolve in hosts of brood parasitic birds that evict nest-mates. Yet, an earlier study showed that host reed warblers ( Acrocephalus scirpaceus ) of an evicting parasite, the common cuckoo ( Cuculus canorus ), can avoid the costs of prolonged care for unrelated young by deserting the cuckoo chick before it fledges. Desertion was not based on specific recognition of the parasite because hosts accept any chick cross-fostered into their nests. Thus, the mechanism of this adaptive host response remains enigmatic. Here, I show experimentally that the cue triggering this ‘discrimination without recognition’ behaviour is the duration of parental care. Neither the intensity of brood care nor the presence of a single-chick in the nest could explain desertions. Hosts responded similarly to foreign chicks, whether heterospecific or experimental conspecifics. The proposed mechanism of discrimination strikingly differs from those found in other parasite–host systems because hosts do not need an internal recognition template of the parasite's appearance to effectively discriminate. Thus, host defences against parasitic chicks may be based upon mechanisms qualitatively different from those operating against parasitic eggs. I also demonstrate that this discriminatory mechanism is non-costly in terms of recognition errors. Comparative data strongly suggest that parasites cannot counter-evolve any adaptation to mitigate effects of this host defence. These findings have crucial implications for the process and end-result of host–parasite arms races and our understanding of the cognitive basis of discriminatory mechanisms in general.