Dominant nestlings displaying female-like melanin coloration behave altruistically in the barn owl

AbstractBird nests are specialized habitats because of their particular composition including nest detritus and bird droppings. In consequence, they attract a specialized arthropod community considered as nidicolous, which includes species only found in bird nests (strictly nidicolous) or sometimes found in bird nests (facultatively nidicolous). Because the factors influencing the entomofauna in bird nests are poorly understood, in autumn 2019, we collected nest material in 86 Barn Owl (Tyto alba) nest boxes. We investigated whether the invertebrate species richness was related to Barn Owl nest box occupancy, the density of available nest boxes and the landscape structure. We found 3,321 nidicolous beetle specimens belonging to 24 species. Species richness of strictly nidicolous beetles was 2.7 times higher in nest boxes occupied by a family of Barn Owls the previous spring compared to unoccupied nest boxes. It was also higher in sites that were more often occupied by Barn Owls in the five previous years and in areas surrounded by a higher proportion of crop fields. For facultatively nidicolous beetles, the density of Barn Owl nest boxes enhanced the species richness. In conclusion, our study suggests that the strictly nidicolous beetles benefit from occupied nest boxes of Barn Owls, whereas facultatively nidicolous beetles look for nest boxes independently of whether Barn Owls occupy them. Our study highlights the importance of bird nests for a suite of invertebrates.

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Vertebrate Remains in Pellets of the Barn Owl, Tyto Alba, From Planet Downs Station, South-Western Queensland.

Wildlife Research ◽

10.1071/wr9810181 ◽

1981 ◽

Vol 8 (1) ◽

pp. 181 ◽

Cited By ~ 5

Author(s):

A Valente

Keyword(s):

Mus Musculus ◽

Prey Item ◽

Barn Owl ◽

Tyto Alba ◽

Sminthopsis Macroura

Vertebrate remains in a collection of barn owl (Tyto alba) pellets from south-western Queensland were largely those of mammals, including Rattus villosissimus, Mus musculus, Leggadina forresti, Planigale tenuirostris, Sminthopsis macroura and S. crassicaudata. R. villosissimus was the most common prey item. P. tenuirostris had not been recorded previously from the area. Other vertebrate remains included those of birds, lizards and frogs. Some insects were also found in the pellets.

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Breeding and reintroduction of the Barn owl

International Zoo Yearbook ◽

10.1111/j.1748-1090.1984.tb03008.x ◽

2007 ◽

Vol 23 (1) ◽

pp. 88-95

Author(s):

TONY WARBURTON

Keyword(s):

Barn Owl

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Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020988229 ◽

2021 ◽

pp. 095441002098822

Author(s):

Dian Li ◽

Xiaomin Liu ◽

Lei Wang ◽

Fujia Hu ◽

Guang Xi

Keyword(s):

Flow Field ◽

Noise Reduction ◽

Numerical Study ◽

Barn Owl ◽

Aerodynamic Noise ◽

Frequency Noise ◽

Trailing Edge ◽

Reduction Mechanisms ◽

Trailing Edge Serrations ◽

Bionic Airfoil

Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.

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