The effects of drought on prey selection of the barn owl (Tyto alba) in the Strzelecki Regional Reserve, north-eastern South Australia

2009 ◽  
Vol 31 (1) ◽  
pp. 47 ◽  
Author(s):  
Matthew C. McDowell ◽  
Graham C. Medlin
Keyword(s):  
Prey Selection ◽  
South Australia ◽  
Barn Owl ◽  
Tyto Alba ◽  
Dry Period ◽  
Sminthopsis Crassicaudata ◽  
North Eastern ◽  
Barn Owls ◽  
Effects Of Drought ◽  
Selection Of

Changes in the diet of the barn owl (Tyto alba) were determined by analysing 619 egested pellets collected in eight samples over 12 months from a roost in the Strzelecki Regional Reserve, north-eastern South Australia. These data were used to examine the occurrence and change in frequency of small vertebrates in the region. In January 2003, at the end of a prolonged dry period, reptiles (predominantly geckos) dominated the diet of the barn owl, forming over 74% of Prey Units (PU%). This is the first Australian study to report reptiles as the primary prey of the barn owl. After substantial rain in February 2003, mammalian prey became much more common, and eventually accounted for almost 80 PU%. At least nine species of small mammal, at least four reptiles, nine birds and a frog were identified from the pellets. Mammalian prey included Leggadina forresti, Mus musculus, Notomys fuscus (endangered), Pseudomys desertor (not previously recorded in the reserve), P. hermannsburgensis, Planigale gilesi, Sminthopsis crassicaudata, S. macroura and Tadarida australis. This research showed that barn owls are capable of switching to alternative prey when mammals become rare, but that they return to preferred prey as soon as it becomes available.

Feeding Ecology of the Barn Owl, Tyto Alba, in Arid Southern Australia.

1979 ◽  
Vol 6 (2) ◽  
pp. 191 ◽  
Author(s):  
SR Morton ◽  
AA Martin
Keyword(s):  
Feeding Ecology ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
Barn Owl ◽  
Tyto Alba ◽  
South Wales ◽  
Barn Owls ◽  
The Mean ◽  
Study Sites

In arid parts of Australia the barn owl appears to feed largely on rodents which form irruptions or plagues, i.e. undergo marked changes in abundance. Barn owls became common at the height of an irruption of house mice, Mus musculus, in western New South Wales, but were comparatively scarce after the mice decreased in numbers. There was some evidence that the owls' diet, determined by analysis of pellets, was more varied immediately after the numbers of mice decreased, but its major part still consisted of M. musculus. The mean number of prey units represented in each pellet rose during the irruption and then declined to the original level. At a variety of sites in arid New South Wales and South Australia, barn owls' diet consisted almost entirely of small mammals. The most common prey species were rodents that fluctuate widely in abundance, and the mean amount of prey per pellet differed greatly among the study sites. The feeding ecology of barn owls in arid Australian environments is essentially similar to that described for more mesic habitats; hence, a greatly increased variation in the abundance of mammalian prey has not led to an increase in breadth of food niche.

scholarly journals Nidicolous beetle species richness is driven by Barn Owl’s nests occupancy and landscape structure

2021 ◽  
Author(s):  
Vivien Cosandey ◽  
Robin Séchaud ◽  
Paul Béziers ◽  
Yannick Chittaro ◽  
Andreas Sanchez ◽  
...  
Keyword(s):  
Species Richness ◽  
Landscape Structure ◽  
Barn Owl ◽  
Arthropod Community ◽  
Tyto Alba ◽  
Nest Material ◽  
Crop Fields ◽  
Nest Boxes ◽  
Bird Droppings ◽  
Barn Owls

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.

Effects of environmental temperature on thyroid hormones in the barn owl (Tyto alba)

2006 ◽  
Vol 54 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Á. Klein ◽  
Margit Kulcsár ◽  
Virág Krízsik ◽  
R. Mátics ◽  
P. Rudas ◽  
...  
Keyword(s):  
Plasma Level ◽  
Thyroid Hormones ◽  
Environmental Temperature ◽  
Barn Owl ◽  
Breeding Period ◽  
Tyto Alba ◽  
Lower Plasma ◽  
Cell Level ◽  
Trh Stimulation ◽  
Barn Owls

The basic patterns of thyroid hormones [thyroxine (T4) and 3,3',5-triiodothyronine (T3)] and the T4 and T3 responses induced by thyrotropin releasing hormone (TRH) are reported in captive female barn owls (Tyto alba) during the non-breeding period. The main findings of the study, conducted on a total of 10 owls, are as follow: (1) The thyroid gland of barn owl can be stimulated by the classical TRH stimulation test. (2) T3 response was much more pronounced both under cold (around 10°C) and warm (around 20°C) conditions, whereas T4 response ranged so widely that we could not point out any significant change in it. (3) Basal T3 plasma level was significantly (p = 0.036) higher in birds exposed to cold temperature, and they responded to TRH treatment with a lower plasma T3 elevation than the birds kept in a warm chamber. This pattern, however, cannot be explained by increased food intake, but is in agreement with the fact that enhanced T3 level may account for higher avUCP mRNA expression, which results in higher heat production on the cell level. From the results it is concluded that altering T3 plasma level plays a significant role in cold-induced thermoregulation.

scholarly journals Offspring Desertion by Double-Brooded Female Barn Owls (Tyto Alba)

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 515-519 ◽  
Author(s):  
Alexandre Roulin
Keyword(s):  
Breeding Success ◽  
Barn Owl ◽  
Nesting Success ◽  
Reproductive Cost ◽  
Tyto Alba ◽  
Barn Owls ◽  
Breeding Attempt ◽  
Second Clutch ◽  
Offspring Desertion

Abstract In double-brooded species, the sex that contributes less to breeding success may desert offspring before the end of the rearing period to start a new breeding attempt with another partner. I evaluated that prediction in the Barn Owl (Tyto alba), a species in which the male feeds the brood on average twice as often as the female. Among birds that produced a second brood, 46% of females and 4% of males deserted their offspring before completion of parental duties to remate with another partner at a distance of 1 to 10 km. Offspring desertion did not appear to incur a reproductive cost to the deserter, because deserting females at the first nest produced a similar number of offspring as nondeserting ones. In most cases, the new mate of deserting females had not been previously captured in the study area, and hence had probably not previously bred that season. Although the second clutch of deserting females was larger and produced two weeks earlier than that of nondeserting females, their nesting success did not differ.

Bioenergetics and Prey Selection of Captive Barn Owls

The Condor ◽  
1976 ◽  
Vol 78 (1) ◽  
pp. 139-141 ◽  
Author(s):  
Lorna G. Wallick ◽  
Gary W. Barrett
Keyword(s):  
Prey Selection ◽  
Barn Owls ◽  
Selection Of

Prey selection by barn owls in relation to small-mammal community and population structure in a Sahelian agro-ecosystem

2007 ◽  
Vol 23 (2) ◽  
pp. 199-208 ◽  
Author(s):  
Laurent Granjon ◽  
Mahamane Traoré
Keyword(s):  
Small Mammal ◽  
Prey Selection ◽  
Population Level ◽  
Tooth Wear ◽  
Barn Owl ◽  
Reproductive Period ◽  
Site Distribution ◽  
Barn Owls ◽  
Small Mammal Community ◽  
Major Shift

Barn owl pellet content was studied on seven occasions over a 2-y period during which terrestrial small-mammal populations were assessed via a capture-mark-recapture (CMR) programme in a Sahelian agro-ecosystem of the Inner Delta of Niger River in Mali. Rodents (especially Mastomys huberti representing 78.5% of the total number of prey) were the major prey of the barn owl on all but one occasion, when bats were dominant. This exception coincided with the period of lowest abundance of M. huberti at the study site. Distribution of M. huberti prey into four age classes was assessed through analysis of tooth wear in remains from the seasonal pellet samples. Comparisons with age structure of the CMR population indicate that the barn owl tended to prey on smaller-than-average (thus younger) individuals, especially when these are rare in the population (non-reproductive period between June and October). The spectrum of prey consumed is compared with data previously reported in Sahelian Africa, showing for the first time in this region a major shift in prey choice by the barn owl when its preferred prey becomes rare. At the rodent population level, the apparent choice of younger M. huberti prey at some periods is interpreted in the light of our knowledge on population dynamics of the species in this habitat.

scholarly journals Distribution, population density and habitat preferences of the Barn Owl (Tyto alba) in Sliven and Yambol districts, SE Bulgaria

2019 ◽  
Vol 2 ◽  
Author(s):  
Girgina Daskalova ◽  
Peter Shurulinkov ◽  
Georgi Popgeorgiev
Keyword(s):  
Habitat Preferences ◽  
Barn Owl ◽  
Average Density ◽  
Tyto Alba ◽  
Forest Patches ◽  
Rare And Endangered Species ◽  
Barn Owls ◽  
Rare And Endangered ◽  
Occupied Territories ◽  
Data Book

The Barn Owl (Tyto alba Gould, 1837) is a rare and endangered species in Bulgaria, included in the Red Data Book (Golemansky 2015) as “Vulnerable”, with national population estimated at 200–700 pairs. Barn Owl presence was surveyed using sound provocation during the night at 161 points in 52 small to medium-sized settlements in Sliven and Yambol districts (Thracian plain, SE Bulgaria). The studied territory was about 1190 km2. The habitats presented in a 3-km radius around the presence and potential absence points were statistically analysed. The species was found to be a quite common breeding species in the study area – a total of 56 Barn Owls were registered, at 50 points (31.1%), in 31 settlements (62% of all studied). Clear defensive behavior was observed against the source of the sound in many occasions. The average density of the population was 4.2 occupied territories / 100 km2. The occupied locations were situated mostly in settlements laying in deforested lowland areas (far from large forest patches), with flat or hilly relief, covered by agricultural lands, pastures and steppes. The number of presences was found to be scarce in villages along heavily used motorways. Traffic-caused mortality of Barn Owls is commented as a probable explanation.

Diets of native and introduced apex predators in Hawai'i

2018 ◽  
Vol 24 (1) ◽  
pp. 25
Author(s):  
Carolyn S. Mostello ◽  
Sheila Conant
Keyword(s):  
Barn Owl ◽  
Tyto Alba ◽  
Apex Predators ◽  
Mammal Species ◽  
Feral Cat ◽  
Arthropod Species ◽  
Significant Difference ◽  
Before And After ◽  
Asio Flammeus ◽  
Barn Owls

We report here on the diets of four apex predators in Hawai‘i: the native pueo or Hawaiian short-eared owl (Asio flammeus sandwichensis) and three introduced species, the barn owl (Tyto alba pratincola), the feral cat (Felis catus) and the small Indian mongoose (Herpestes javanicus). To better understand dietary relationships between these predators, we studied diet, focusing on areas where they occur together. We collected disgorged owl pellets, and cat and mongoose faecal scats from eight areas located on five of the main Hawaiian Islands and identified prey items to the lowest possible taxonomic level. All species consumed rodents, birds, and arthropods, and the mammal species also included plants in their diets. The two owl species and the cat preyed primarily on rodents, whereas small cockroaches predominated in the diet of the mongoose. Diets of the owl species and the cat, but not the mongoose, varied significantly between areas. Dietary overlap was highest between the pueo and the barn owl and lowest between the owl species and the mongoose. Although barn owls took more rats than pueo, there was no evidence that the two owl species partitioned house mouse prey by size. On islands where there are no mongoose, both owls took a greater proportion of large arthropods in their diet, suggesting that mongoose reduced the abundance of the arthropod species that owls commonly took. There was no significant difference in pueo diets before and after introduction of the barn owl.

scholarly journals Non-Vocal Behaviors Are More Frequent During the Decisive Negotiation Phases in Barn Owl Siblings

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1777
Author(s):  
Amélie N. Dreiss ◽  
Andrea Romano ◽  
Raphaëlle Flint ◽  
Sarah Bates ◽  
Aurélie Vermunt ◽  
...  
Keyword(s):  
Signal Transmission ◽  
Barn Owl ◽  
Negotiation Process ◽  
Tyto Alba ◽  
Body Movements ◽  
Hunger Level ◽  
Sibling Negotiation ◽  
Turn Taking ◽  
Barn Owls ◽  
Vocal Interactions

Animals produce vibrations or noises by means of body movements, which can play a role in communication. These behaviors enhance signal transmission or receiver attention and could be specifically used during turn-taking phases of a reciprocal exchange of signals. In the barn owl Tyto alba, nestlings vocalize one after the other to negotiate which individual will have priority access to the impending prey item to be delivered by the parents. Owlets adjust their vocalization to their own hunger level and to their siblings’ vocalization, withdrawing from the contest in front of highly vocal, and hence hungry, motivated nestmates. As sibling negotiation is a multicomponent display, we examined whether body movements could also be part of the negotiation process. To this end, we analyzed whether the vocalizations of one nestling affected its nestmate’s movements in three separate experiments: in natural nests, in the lab, and using a playback procedure. Nestling barn owls move in a variety of ways, such as repeated tapping of the floor with a foot, scratching the floor with claws, or flapping wings. Body movements were more frequent during the turn-taking phases of vocal interactions, when siblings emitted longer calls and at a greater rate. Once an individual monopolized vocal activity, siblings became less vocal and less active. Moreover, owlets produced more noisy body movements during the phases of vocal interactions which are crucial to prevail in negotiation. Non-vocal physical activities might reinforce vocal signals during sibling to sibling (sib–sib) interactions, or reflect owlets’ arousal, in the critical period during which they vocally settle which individual will dominate the competition.

The Relationship between Weather and Reproduction of the Barn Owl Tyto Alba in a Semi-Arid Agricultural Landscape in Israel

2017 ◽  
Vol 10 (4) ◽  
pp. 253-258 ◽  
Author(s):  
Motti Charter ◽  
Ido Izhaki ◽  
Kobi Meyrom ◽  
Shauli Aviel ◽  
Yossi Leshem ◽  
...  
Keyword(s):  
Agricultural Landscape ◽  
Breeding Population ◽  
Barn Owl ◽  
Tyto Alba ◽  
Cold Temperatures ◽  
Ambient Temperatures ◽  
Barn Owls ◽  
Negative Effect ◽  
Minimum Daily Temperature ◽  
Semi Arid

Even though the Barn Owl ( Tyto alba) is distributed worldwide, little information is available on how weather affects Barn Owl breeding outside of Europe and North America. For instance, if cold temperatures can negatively influence population dynamics in temperate regions, heat could have a similar negative effect in arid regions. We have studied a breeding population of Barn Owls in a semi-arid agricultural environment over 13 years in Israel in order to determine whether lack of rain and hot ambient temperatures impair Barn Owl reproductive success. The percentage of nest boxes occupied by Barn Owls was not related to any of the weather variables, whereas the number of nestlings per Barn Owl pair and the percentage of pairs that succeeded to fledge young was lower in years when it started to rain later in the season and when the minimum daily temperature was higher during the breeding season. In comparison to temperate regions, heat is detrimental to Barn Owl breeding and early precipitation is probably important in boosting vegetation and, in turn, the abundance of small mammals, the Barn Owl's staple food.

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