Emigration behavior of Clark's Nutcracker

Journal ArticleEruptive movements of the Clark's Nutcracker (Nucifraga columbiana) were observed during the late summer and fall of 1977, 1978 and 1979 in northern Utah and adjacent states. Over 2,000 emigrating nutcrackers were seen during these periods. Eruptions began in mid to late August, about the time nutcrackers began foraging on developing conifer cones, and continued until early October. Nearly all nutcrackers traveled in small, loose flocks (x = 10.1 individuals). During 1977-1978, most emigrating nutcrackers appeared to winter in p&on-juniper woodlands of Utah and adjacent states and no nutcrackers were reported outside their normal breeding range. A northward movement of nutcrackers, presumably the same population observed emigrating southward in fall 1977, was noted in summer 1978. Evidence for breeding of nutcrackers on their wintering areas is presented. A compartmental model summarizes current knowledge on the temporal and spatial aspects of nutcracker emigration

Use of a geometric rule or absolute vectors: Landmark use by Clark’s nutcrackers (\u3ci\u3eNucifraga columbiana\u3c/i\u3e)

Clark’s nutcrackers (Nucifraga columbiana) were trained to search for a hidden goal located in the center of a four-landmark array. Upon completion of training, the nutcrackers were presented with tests that expanded the landmark array in the east-west direction, north-south direction and in both directions simultaneously. Although the birds learned to search accurately at the center of the landmark array during training, this search pattern did not transfer to the expansion tests. The nutcrackers searched at locations defined by absolute distance and/or direction relationships with landmarks in the training array. These results contrast with those from experiments with nutcrackers in which an abstract geometric rule was learned. This difference appears due to differences in the experimental paradigms used during training

Interference Effects in the Memory for Serially Presented Locations in Clark’s Nutcrackers, Nucifraga columbiana

The authors tested the spatial memory of serially presented locations in Clark’s nutcrackers (Nucifraga columbiana). Birds were serially presented with locations in an open room. The authors buried a seed in a sand-filled cup at each location and then tested nutcrackers for their memory for each location in the list by using the cluster method. For each item in the list, the authors opened a cluster of 6 holes. Accuracy was measured by how many tries were required for the bird to find the correct location within each cluster. In Experiments 1 and 2, the authors presented 2 lists of locations and found evidence for proactive and retroactive interference. Nutcrackers made errors by visiting the interfering list of locations during recovery of the target list. This finding demonstrates that nutcrackers are susceptible to proactive and retroactive interference during the recall of spatial information

Individual exploratory responses are not repeatable across time or context for four species of food-storing corvid.

Exploration is among one of the most studied of animal personality traits (i.e., individual-level behavioural responses repeatable across time and contexts). However, not all species show clear evidence of this personality trait, and this is particularly so for members of the Corvidae family. We assessed the exploratory behaviour of four food-caching corvid species: pinyon jays (Gymnorhinus cyanocephalus), Clark's nutcrackers (Nucifraga columbiana), California scrub jays (Aphelocoma californica), and black-billed magpies (Pica hudsonia). Contextual repeatability was assessed through examining behavioural measures during the Novel Environment task and the Novel Object task, whereas temporal repeatability was assessed by examining changes in these measures over repeated trials. Our results suggest that, for corvids, an individual's exploratory behaviour was not repeatable across contexts or over time. Hence, we found no evidence that exploration constitutes a personality trait for these species of corvid. We did find differences in exploratory behaviour, at a species level, that may be explained by relative reliance on cached food

About the degree of scrutiny consorting links slender-billed nutcrackers Nucifraga caryocatactes L. and siberian stone pine Pinus sibirica Du tour

Проведено обобщение широко известных закономерностей и освещение малоизвестных фактов во взаимосвязях сосны сибирской (Pinus sibirica Du Tour) и ее основного распространителя – кедровки тонкоклювой (Nucifraga caryocatactes L.). Кедровка выполняет важную роль в лесообразовательном процессе сосны кедровой. Представлен аналитический обзор работ зоологической и орнитологической направленности с конвергенцией результатов с устоявшимися закономерностями в лесоведении. Потребителями кедровых орехов являются 23 вида птиц и 10 видов млекопитающих, которые поедают до 97 % урожая. Единственным же распространителем является кедровка, которая поедает до 50 % орехов, а остальной урожай служит для воспроизводства кедра на расстояние 2–4 км, т.е. более чем в 10 раз дальше других хвойных видов. Отмечается, что кедровка уничтожает насекомых во взрослой стадии развития (имаго). Поедая самок дооткладки ими яиц, кедровка тем самым предотвращает заселение деревьев. Наибольшее количество орехов (до 90 % запасов) кедровка прячет в подстилке, пнях и валежинах и лишь 3–5 % захоронок располагается на ровных местах. Только незначительная часть запасов кедровки (3–15 %) идет на возобновление кедра, которое не зависит от общего размера урожая. При этом отмечается, что 15,4 % ореха выносится за пределы кедровника. В целом прослеживается отчетливая цепь консортивных связей: численность всходов кедра в тот или иной год наиболее тесно связана с урожаем орехов два года назад, детерминирующим обилие кедровки и распространённых ею семян на будущий год, которое, в свою очередь, определяет обилие всходов кедра на следующий год.The generalization of the known patterns and the description of little-known facts of relationship of Siberian pine (Pinus sibirica Du Tour) and slender-billed nutcrackers (Nucifraga caryocatactes L.). The Nutcracker spreads the seeds of Siberian pine. The Nutcracker plays an important role in forest forming process cedar pine tree. Presents an analytical survey of the work of Zoological and ornithological orientation. Conducted convergence of the results with the patterns of forest science. Consumers of pine nuts are 23 species of birds and 10 species of mammals that eat up to 97 % yield. The only distributor is the Nutcracker, which eats up to 50 % nuts. The rest of the harvest is used for reproduction of cedar at a distance of 2–4 km, which is more than 10 times further than other conifer species. Nutcracker consumes insects in the adult stages (imago). Nutcracker eats the females to lay their eggs. This prevents the colonization of trees by insects. The greatest number of nuts (up to 90 % of reserves), the Nutcracker hides in the forest litter, stumps and fallen trees and 3-5 % of the seeds were located on level ground. A small part of the reserves nutcrackers (3–15 %) is the resumption of cedar, which does not depend on the overall size of the harvest. 15.4 % of the nut is made outside spaces. Traced a clear chain consorting ties: the number of cedar seedlings is closely linked with the crop of nuts two years ago, determining the abundance of nutcrackers, and common of its seeds for next year, which in turn determines the abundance of cedar seedlings for next year

Invasive Pathogen Threatens Bird-Pine Mutualism: Implications for Sustaining a High-Elevation Ecosystem

Human-caused disruptions to seed-dispersal mutualisms increase the extinction risk for both plant and animal species. Large-seeded plants can be particularly vulnerable due to highly specialized dispersal systems and no compensatory regeneration mechanisms. Whitebark pine ( Pinus albicaulis), a keystone subalpine species, obligately depends upon the Clark\u27s Nutcracker (Nucifraga columbiana) for dispersal of its large, wingless seeds. Clark\u27s Nutcracker, a facultative mutualist with whitebark pine, is sensitive to rates of energy gain, and emigrates from subalpine forests during periods of cone shortages. The invasive fungal pathogen Cronartium ribicola, which causes white pine blister rust, reduces whitebark pine cone production by killing cone-bearing branches and trees. Mortality from blister rust reaches 90% or higher in some whitebark pine forests in the Northern Rocky Mountains, USA, and the rust now occurs nearly rangewide in whitebark pine. Our objectives were to identify the minimum level of cone production necessary to elicit seed dispersal by nutcrackers and to determine how cone production is influenced by forest structure and health. We quantified forest conditions and ecological interactions between nutcrackers and whitebark pine in three Rocky Mountain ecosystems that differ in levels of rust infection and mortality. Both the frequency of nutcracker occurrence and probability of seed dispersal were strongly related to annual whitebark pine cone production, which had a positive linear association with live whitebark pine basal area, and negative linear association with whitebark pine tree mortality and rust infection. From our data, we estimated that a threshold level of similar to 1000 cones/ha is needed for a high likelihood of seed dispersal by nutcrackers ( probability \u3e= 0.7), and that this level of cone production can be met by forests with live whitebark pine basal area \u3e5.0 m(2)/ha. The risk of mutualism disruption is greatest in northernmost Montana ( USA), where three-year mean cone production and live basal area fell below predicted threshold levels. There, nutcracker occurrence, seed dispersal, and whitebark pine regeneration were the lowest of the three ecosystems. Managers can use these threshold values to differentiate between restoration sites requiring planting of rust-resistant seedlings and sites where nutcracker seed dispersal can be expected

An investigation of non-spatial cognitive abilities in an asocial corvid, the Clark\u27s nutcracker (Nucifraga columbiana)

A great deal of research suggests that the cognitive abilities of birds in the family Corvidae (crows and jays) are comparable in many aspects to that of apes. Scientists have posited competing hypotheses to explain how complex cognitive abilities arise in a species or group of animals. One such hypothesis, the social-intelligence hypothesis, states that the demands of living in a large, dynamic group drive an animal\u27s need for complex cognitive skills. The ecological-intelligence hypothesis, predicts that generalist foragers develop more highly flexible behaviors and a wider cognitive repertoire than specialist foragers. To date, cognitive research on corvids has focused on corvids that are highly social and are generalist foragers. From a comparative standpoint, I examined the cognitive abilities of a corvid that is relatively asocial and a specialist forager. The Clarks\u27 nutcracker (Nucifraga columbiana) is thought to be perhaps the least social corvid, and it largely specializes on the seeds of one species of pine (Pinus edulis). I tested nutcrackers using several tasks in three broad areas of cognition: inferential reasoning, numerical discrimination, and social intelligence. These experiments represent novel tests of cognitive abilities in this species. I found that the nutcrackers performed in a similar manner as social mammals and corvid birds, in all three areas of cognition. This suggests that social group size may not have a large impact on the development of a broad range of problem solving skills. Rather, ecological pressures associated with finding, extracting, caching and protecting seeds from pilferage may have influenced the development of complex cognition in this species