A test of the predator avoidance hypothesis to explain delayed onset of communal breeding

2019 ◽  
Vol 97 (4) ◽  
pp. 332-339
Author(s):  
D. Strickland ◽  
E. Brouwer ◽  
T.M. Burg

A neglected question in the study of communal breeding concerns why alloparental behaviour begins at variously late stages in the breeding cycle. In group-living corvids, the delay tends to be longer in species that are small and (or) typically have only a small nonbreeder complement. This pattern has been attributed to the relatively poor defensive capabilities of such species and their consequently greater need to minimize predator-attracting traffic to the nest or fledglings. We tested this predator avoidance hypothesis with the Canada Jay (Perisoreus canadensis (Linnaeus, 1766)), a species in which the feeding of young by any nonbreeders in the family group is delayed until the fledgling period. We reasoned that, on Anticosti Island, Quebec (Canada), in the absence of squirrels and other nest predators, nonbreeders might be permitted to feed nestlings as well as fledglings, and that breeders might feed nestlings more frequently (with smaller food loads) than on the mainland. We found no evidence for either prediction and thus no support for the predator avoidance hypothesis but suggest that Anticosti Canada Jays may have had insufficient time to evolve behaviour more appropriate for their predator-free environment. Secondarily, we confirmed that in all observed instances, the nonbreeders were offspring of the breeding pair from previous years and that they therefore failed to provision nestlings in spite of an apparent genetic interest to do so.

2001 ◽  
Vol 79 (12) ◽  
pp. 2128-2146 ◽  
Author(s):  
Dan Strickland ◽  
Thomas A Waite

A neglected question in the study of communal breeding in birds concerns why alloparenting begins at variously late stages in the nesting cycle. We studied this phenomenon in the Gray Jay (Perisoreus canadensis), a species in which nonbreeders are excluded from the nest area by parental hostility and begin to feed young only during the fledgling period. We hypothesize that this pattern is favoured because of the risk of nest predation. By initially suppressing allofeeding, Gray Jay parents may reduce the frequency of predator-attracting visits to the nest when the young are most vulnerable. We evaluated this predator-avoidance hypothesis in a six-part meta-analysis using observations of 111 philopatric and immigrant nonbreeders associated with 647 pairs over 33 years and nest-visitation data for 307 other passerines. First, we found indirect evidence that Gray Jays and other corvids with non-allofeeding nonbreeders do reduce nest visitation by excluding nonbreeders. Second, we found that the hostility of adult Gray Jays towards nonbreeders peaks during the incubation and nestling periods, is stronger closer to the nest, and is directed towards both related and unrelated nonbreeders. We then found support for four predictions stemming from the predator-avoidance hypothesis. Compared with species having allofeeding nonbreeders, the Gray Jay and other corvids with non-allofeeding nonbreeders are characterized by (i) smaller clutches; (ii) lower parental nest-visitation rates (a consequence of larger food loads); (iii) a greater increase in parental feeding visits after fledging, paralleling the simultaneous relaxation of parental hostility towards potential allofeeders; and (iv) a smaller body size and smaller social groups, rendering them less able to deter nest predators. We discuss the potential value of the predator-avoidance perspective for understanding the occurrence or absence of allofeeding in other birds.


The Auk ◽  
1979 ◽  
Vol 96 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Shoshana Ashkenazie ◽  
Uriel N. Safriel

Abstract Pair formation of Calidris pusilla near Barrow, Alaska occurs 3-6 days after the territory is established. The pair is then engaged in nest scraping displays during 2-3 days, in which 10-12 scrapes are made by the male and examined by the female. Eventually 2-3 scrapes are lined by the female, and in one of these the first egg is laid 4-6 days after pairing. During the egg-laying period further lining is performed by the female and partial incubation takes place by both sexes. Continuous incubation commences 8 h prior to laying of the 4th egg. Male and female alternate in incubation: in the first 2 days a turn lasts 3-5 h, and the duration gradually increases up to 13-14 h during the 2nd week. Long incubation turns reduce the number of approaches to the nest and may therefore reduce the chances of it being discovered by predators. The incubating bird is intermittently engaged in egg-rolling and in camouflaging the nest by bending adjacent grass blades over its back, and is constantly alert. The off-duty bird may feed 2-3 km away from the nest. The eggs hatch after 20 days of incubation, all within 1 day. Females desert the family 2-8 days after hatching: they desert late if hatching is early, and early if hatching is late in the season. After female departure the family moves from the nesting territory, typically in a high-centered polygonal area, to establish a home range as far as 2-3 km away, often in a low-centered polygonal area. During the first 6-8 days after hatching, the male prepares each evening a scrape for night brooding. After fledging, the male and young join wandering flocks.


The Auk ◽  
2004 ◽  
Vol 121 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Valentin Amrhein ◽  
Hansjoerg P. Kunc ◽  
Marc Naguib

Abstract Seasonal patterns of singing activity of male birds have been thoroughly studied, but little is known about how those patterns vary with time of day. Here, we censused mated and unmated male Nightingales (Luscinia megarhynchos) at four different hours of the day throughout the breeding cycle. In unmated males, singing activity increased until the young hatched in their neighborhood, and the seasonal variation was similar at each of the four hours of the day. In mated males, however, the seasonal patterns of singing activity differed between hours of the day. In morning (about the hour of egg-laying) and during the dusk chorus, the singing activity of mated males was strongly influenced by the females' reproductive state: singing activity was low before egg-laying and during incubation, but high during the egg-laying period. In the dawn chorus, however, singing activity showed a similar seasonal pattern in mated and unmated males and was high until late stages of the breeding cycle. Our results suggest that the social context influences singing behavior to a varying degree across the season, and that this variation also depends on time of day. The hour of data collection thus is an important but often neglected factor when seasonal changes of singing activity are studied.


Zootaxa ◽  
2013 ◽  
Vol 3637 (5) ◽  
pp. 569 ◽  
Author(s):  
DAVID A. SÁNCHEZ

Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the Dendrobatoidea have similar disposition of digestive organs in early stages, but differentiate in late stages of development. Classifying the upper jaw sheath into the two recognized states is possible from very early stages of development, but gut disposition and nostril ornamentation cannot be determined until late in development, making classification and taxonomic assignment of tadpoles based on these morphological features challenging.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Lisa F Gill ◽  
Wolfgang Goymann ◽  
Andries Ter Maat ◽  
Manfred Gahr

Vocal signals such as calls play a crucial role for survival and successful reproduction, especially in group-living animals. However, call interactions and call dynamics within groups remain largely unexplored because their relation to relevant contexts or life-history stages could not be studied with individual-level resolution. Using on-bird microphone transmitters, we recorded the vocalisations of individual zebra finches (Taeniopygia guttata) behaving freely in social groups, while females and males previously unknown to each other passed through different stages of the breeding cycle. As birds formed pairs and shifted their reproductive status, their call repertoire composition changed. The recordings revealed that calls occurred non-randomly in fine-tuned vocal interactions and decreased within groups while pair-specific patterns emerged. Call-type combinations of vocal interactions changed within pairs and were associated with successful egg-laying, highlighting a potential fitness relevance of calling dynamics in communication systems.


Author(s):  
Likhomanova N.O.

The purpose of the research is to define “family narrative” term; to analyze its structure as well as typological features in “Bukova Zemlya” [Beech Land]. Panorama-novel covering 225 years” by M. Matios published in 2019.Methods have been designed in compliance with the key principles of narratology (particularly, works by Roland Barthes, Gérard Genette, Yury Lotman, Vladimir Propp, Wolf Schmid, etc), the inter-relation of narration types as well as the implemented forms of memory’s reproduction.Results. The author of the research has suggested a definition of “family narrative” term as a form of transformation of cultural, historical and communicative memory. The author has identified and analyzed its structure, key functions, typological and individual features using “Bukova Zemlya” novel by M. Matios. The text of the novel is built as a linear narrative of four families during 225 years in XVIII-XX centuries at the territory of Bukovyna (currently, in the South-West of Ukraine). According to G. Genette’s typology, the impartiality of the story is achieved via conducting a narration on behalf of a heterodiegetic narrator in an extradiegetic situation. Combination of a family and a historical narratives is typologically manifested through detailed descriptions of ancestry trees; family stories; ethnography-styled descriptions of customs and every-day living of Hutsuls [an ethnic group living in Caprathian mountains of Ukraine or nearby]. The author also mentions well-known historical figures, uses testimonies of the individuals who lived in those times found in archive sources on the First World War, protests, rallies and riots in 1918; describes the events of the Second World War, anti-Soviet Resistance in Bukovyna and finishes the novel with the events of the War in Donbas in 2014. Following the classification approach by G. Genette, M. Matios applies an internal focalization of a plural type. In particular, the views of the various characters are presented from the perspective of a heterodiegenetic narrator. For example, one of the novel’s chapters describes a cross-cutting theme of war simultaneously both as viewed by a peasant, Dariy Berehovchuk, and by an ambassador, Nikolay Vasylko. The family narrative includes specific typology features as “sine qua non” components of the plot: birth, marriage, re-location (home/village/city/home country), hardships (diseases, famines, the Holocaust, wars), death. The author’s specific elements of her view upon the family narrative include the themes of Land, the God and belief, Language, Ethnicity (including the topic of multiple ethnic groups living in Bukovyna). The novel also has such popular elements for a family narrative as images of twins (or twin strangers) and some borrowed traditional features of folk epic tales: cases of “magical recognition” and “magical prophecy” for a future of a kin.Conclusions. The family narrative of M. Matios’ novel includes both typology and individual features. It is built in compliance with the structure of the internal focalization of plural type. The narration is presented as conducted by a heterodiegentic narrator in a extradiegenetic situation. Hence, an impartiality of a narration and a subjectivity of a discourse in present time provides for realization of “I”-presence of a reader and avoiding idealization and mythologization of a family narrative, which are quite traditional for it.Key words: narration, heterodiegenetic narrator, historical narrative, cultural memory, communicative memory. Мета – визначити поняття «родинний наратив», проаналізувати його структуру та типологічні ознаки у творі М. Матіос «Букова земля. Роман-панорама завдовжки у 225 років» (2019).Методи дослідження формуються відповідно до основних положень наратології (праці Р. Барта, Ж. Женетта, Ю. Лотмана, В. Проппа, В. Шміда та ін.), взаємозв’язку типу нарації і втілених форм репродукції пам’яті.Результати. У процесі дослідження було запропоновано дефініцію поняття «родинний наратив» як форми трансформації культурної, історичної та комунікативної пам’яті. Визначено та проаналізовано його структуру, основні функції, типологічні та індивідуальні ознаки на прикладі роману М. Матіос «Букова земля». Зазначено, що текст побудований у формі лінійного наративу історії чотирьох родів протягом 225 років на території Буковини XVIII–XXI століть. Об’єктивність викладу досяга-ється, за типологією Ж. Женетта, завдяки нарації від імені гетеродієгетичного наратора в екстрадієгетичній ситуації. Типо-логічною ознакою є поєднання родинного та історичного наративів, що демонструється через детальний опис родоводів, сімейних історій, етнографічного опису побуту та звичаїв гуцулів, згадок про відомих осіб, використання свідчень сучасників з архівних джерел подій Першої світової війни, протестів, мітингів і заворушень 1918 р., подій Другої світової війни, істо-рії антирадянського опору на Буковині та завершення оповіді роману подіями війни на Донбасі у 2014 р. За класифікацією Ж. Женетта, в романі використано внутрішню фокалізацію множинного типу, а саме подаються погляди різних персонажів із точки зору гетеродієгетичного наратора. Наприклад, наскрізна тема війни в одному з епізодів роману одночасно описується з погляду селянина Дарія Береговчука і посла Николая Василька. Типологічними ознаками родинного наративу є і неодмінні складники сюжету: народження, одруження, зміна місця (дому/села/міста/батьківщини), випробування (хвороби, голод, голо-кост, війна), смерть. Виразними елементами авторського погляду на родинний наратив стали теми землі, Бога і віри, мови, національності (зокрема, і тема багатонаціональної буковинської землі). У романі присутні і такі поширені елементи родин-ного наративу, як образи близнюків (або двійників), а також запозичені усталені ознаки сюжетів народного епосу – епізоди чарівного упізнання і магічного передбачення майбутнього роду.Висновки. Родинний наратив роману М. Матіос містить типологічні та індивідуальні ознаки, формується відповідно до структури внутрішньої фокалізації множинного типу. Нарація подається у викладі гетеродієгетичного наратора в екстрадієге-тичній ситуації. Таким чином, об’єктивність оповіді та суб’єктивність дискурсу теперішнього часу дає змогу втілитися ефекту «я»-присутності читача та уникнути традиційної для родинного наративу ідеалізації та міфологізації.Ключові слова: нарація, гетеродієгетичний наратор, історичний наратив, культурна пам’ять, історична пам’ять, комуні-кативна пам’ять.


2018 ◽  
Vol 27 (1) ◽  
pp. 11-33 ◽  
Author(s):  
N.A. Sedova ◽  
S.S. Grigoriev

Larvae of five species of the family Crangonidae (Argis crassa, A. dentata, A. lar, A. ochotensis and A. ovifer) from plankton of east part of Okhotsk Sea and from Avacha Gulf are described. Morphological features of the larvae are compared for purpose of their identification in planktonic samples. The main morphological features of larvae at corresponding stages are revealed. Larvae of these species are similar in most features. Distinctions concern only several details of their structure. Figures of early and late stages of zoea are presented. It is shown that larvae of the genus Argis can have two or three zoeal stages. Generalized morphological characteristic for the larvae of shrimps from the genus Argis is given.


2021 ◽  
Vol 7 (5) ◽  
pp. 3183-3197
Author(s):  
Yang Liu ◽  
Wu Qinyao

Under the background of smoke-free environment, based on the survey data of CMDS 2013 and 2018, this study explored the differences in family migration and residence decisions of migrants living in different neighborhoods, and analyzed the influence of family migration scale on residence decision by using the hierarchical linear model (HLM). The results show that: Peer effects exist in same neighborhoods, while neighborhood effects exist in different neighborhoods, but the effect sizes and directions of various neighborhood factors are different; Family income level is still an important factor affecting the family migration and residence decisions, and the family migration scale has a positive effect on residence decision; There are significant inter-generational differences in family migration and residence decisions, but the conditions for the differences are different; Good neighborhood smoke-free environments and abundant neighborhood activities are helpful to strengthen the family migration and residence decision of migrant workers.


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