Eurasian Jay (Garrulus glandarius)

2020 ◽  
Author(s):  
Steve Madge ◽  
Josep del Hoyo ◽  
David Christie ◽  
Nigel Collar ◽  
Guy M. Kirwan
Keyword(s):  
1974 ◽  
Vol 29 (5-6) ◽  
pp. 239-242 ◽  
Author(s):  
Jens Poltz ◽  
Jürgen Jacob

The uropygial gland fats from four species of the family Corvidae are found to be mainly mono­ ester waxes, which consist of mono-, di-, and trimethyl substituted fatty acids and n- and methyl-branched alcohols. The positions of all methyl brandlings are even-numbered, the 2-position is preferred. About 2 - 40% of the secretions consist of triester waxes: Alkyl-hydroxy-malonic acids esterified with n-fatty acids and n-alcohols. Waxes of this type are very common in the uropygial gland fats of birds and therefore, in opposite to the monoester waxes, they are not usable for a chemotaxo­ nomy of birds.


NeoBiota ◽  
2019 ◽  
Vol 53 ◽  
pp. 25-39
Author(s):  
Łukasz Dylewski ◽  
Łukasz Myczko ◽  
Dean E. Pearson

When alien plant species arrive in a new environment, they develop novel interactions with native biota that can range from negative to positive. Determining the nature and strength of these interactions is integral to understanding why some aliens are suppressed and others become highly invasive pests. For introduced terrestrial plants, seed and seedling interactions with native biota are crucial, because most nascent populations start from seed. Herein, we explored interactions between native generalist rodent and bird consumers and seeds of the invasive wild cucumber Echinocystis lobata by conducting seed-offering experiments in Poland. We also evaluated how interspecific competition from native plants and intraspecific competition from clustering of E. lobata seed (clustering resembling consumer seed caching) affected survival of seedlings and young plants. Native consumers interacted strongly with E. lobata seeds, with rodents removing 98% of seeds from ground locations and birds removing 24% of elevated seeds. Camera and live traps indicated that striped field mice Apodemus agrarius were the predominant rodent removing seeds. Camera traps and visual observations indicated that great tits Parus major and European jays Garrulus glandarius were the primary bird species removing elevated seeds. While some level of seed removal was likely attributable to seed predation, as indicated by seed coat remains, we also observed evidence that rodents may cache E. lobata seeds and Garrulus glandarius are known to cache and disperse seeds. Monitoring of seedlings indicated that increasing cover of native plants and clustering of E. lobata seedlings both reduced survival of seedlings and young plants due to inter- and intraspecific competition, respectively. Hence, caching by generalist consumers may disperse E. lobata seeds, which are heavy and lack dispersal adaptations, but such caching may also reduce individual seedling survival rates. Fully understanding invasion success of the E. lobata will require evaluating the net effects of generalist consumers on its recruitment and dispersal.


Ibis ◽  
2008 ◽  
Vol 138 (2) ◽  
pp. 250-255 ◽  
Author(s):  
N. S. CLAYTON ◽  
R. MELLOR ◽  
A. JACKSON

2019 ◽  
Vol 36 (3) ◽  
pp. 133-138
Author(s):  
Eui-Ju Hong ◽  
Si-Yun Ryu ◽  
Joon-Seok Chae ◽  
Hyeon-Cheol Kim ◽  
Jinho Park ◽  
...  

Ibis ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 331-334 ◽  
Author(s):  
N. S. CLAYTON ◽  
D. GRIFFITHS ◽  
A. T. D. BENNETT
Keyword(s):  

Author(s):  
O. I. Evstigneev ◽  
◽  
I. A. Murashev ◽  
M. S. Romanov ◽  
◽  
...  

2019 ◽  
Author(s):  
Piero Amodio ◽  
Markus Boeckle ◽  
Sarah A. Jelbert ◽  
Ljerka Ostoijc ◽  
Nicola S. Clayton

AbstractEurasian jays (Garrulus glandarius) do not habitually use tools, yet they can be trained to solve object-dropping tasks, i.e. to insert a tool into an apparatus to release a food reward. Previous research suggests the these jays can learn a preference toward functional tools – objects allowing to obtain a food reward placed inside an apparatus – according to their density (Cheke et al., 2011). However, it is not yet known whether they can also select functional tools (tool selectivity) according to other physical properties such as size and shape, and use different kinds of tools to solve a similar task. Here we conducted three object-dropping experiments aimed at exploring these abilities in Eurasian jays. In Experiment 1, jays tended to select large stones as tools irrespective of the diameter of the apparatus. However, jays progressively developed a preference for the small tool, which was functional with both the wide and the narrow apparatuses. In Experiment 2, only vertically-oriented long stones could fit into the narrow apparatus, whereas both long and round stones were functional with the wide apparatus. Jays showed a preference for the long stone and, with the narrow apparatus, tended to achieve the correct manipulation after one or more unsuccessful attempts. In Experiment 3, jays were able to use sticks and adopt a novel technique on the same object-dropping apparatus, thus providing the first evidence that Eurasian jays can use sticks as tools. Taken together, these results indicate that Eurasian jays may have limited tool selectivity abilities but nonetheless can use different kinds of tools to solve similar tasks.


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