Subject: Owl Research News -- 6 April 2020

Owl Research News
A summary of recent owl publications and news.
Change in World Owl Conference Dates Due to COVID-19

Although we hope to be past the grip of COVID-19 by the fall of 2021, it has affected the conference planning of the Raptor Research Foundation. Their conference scheduled for this fall in Boise, Idaho has been postponed until October 2021, just one week prior to our scheduled dates. Their venue had no flexibility in dates for 2021 but ours does. To reduce potential difficulties for people who may wish to attend both conferences we have moved the dates of the World Owl Conference to September 20-24, 2021.
Domahidi, Z., J. Shonfield, S. E. Nielsen, J. R. Spence, and E. M. Bayne. 2019. Spatial distribution of the Boreal Owl and Northern Saw-whet Owl in the Boreal region of Alberta, Canada. Avian Conservation and Ecology 14(2):14.
Using sound recordings from Autonomous Recording Units placed between 2013-2016 in the Boreal Natural Region of Alberta, Canada we extracted presence/absence data to develop distribution models for two cavity-nesting owl species. To characterize each survey site, we used georeferenced data on landscape cover, climate and human disturbance. Average minimum winter temperature had the highest relative contribution to the final distribution model of boreal owls, while the most important predictor of northern saw-whet owl distribution was amount of cropland at the home range scale. Climatic factors were important predicting distribution for both species, with boreal owls often found in cool environments with cold winters, and a low percentage of grassland cover at the landscape scale. Northern saw-whet owls were more likely to be present in areas with cool summer temperatures and less snow, and where cropland was interspersed with deciduous-dominated forests. Human disturbances affected owl distribution differently. Northern saw-whet owls were most often found near openings created by linear disturbances while boreal owls were associated with landscapes containing low levels of linear disturbances. This study provides much needed information on two poorly studied species inhabiting Alberta’s boreal forests and facilitates better landscape and species management in a region that is undergoing rapid change.                                                    
Click here for the full-text article.
Filip Tulis, Tomáš Veselovský, and Simon Birrer 2019. Different alternative diets within two subgroups in a winter roost of long-eared owls. Raptor Journal 13(1): 139-144.
The long-eared owl (Asio otus) is in the whole area of its distribution typical by the creation of winter-roosts. In the environmental conditions of central Europe is this owl considered as a common vole (Microtus arvalis) hunter specialist.
In winter 2013/2014 a winter-roost of long-eared owls (in Bojnice Spa, central Slovakia) was formed by two subgroups situated 12 meters apart from each other. The direction of the owls’ departure from the roost and pellets were was recorded / collected in monthly intervals.
The most hunted prey by the prey number in both subgroups was the common vole. However, comparing the alternative prey of the two subgroups, the wood mouse (Apodemus sylvaticus) and other mammals were found significantly more often in pellets of the 1st subgroup, whereas birds were more frequent in pellets of the 2nd subgroup. Owls in subgroups also used the different directions of roost departures. Our results suggest that the different prey hunted by the two subgroups may be a consequence of diverging hunting areas with different availability of alternative prey species.

Click here for full text article»
Knaus, P.; S. Antoniazza; S. Wechsler; J. Guélat; M. Kéry; N. Strebel, T. Sattler 2018: Swiss Breeding Bird Atlas 2013–2016. Distribution and population trends of birds in Switzerland and Liechtenstein. Swiss Ornithological Institute, Sempach. ISBN: 978-3-85949-013-0.
The state of birdlife reflects our relationship with nature and our landscapes. The Swiss Breeding Bird Atlas 2013–2016 presents the current distribution, abundance and altitudinal distribution of all breeding birds in Switzerland and Liechtenstein with unprecedented precision. Among the 216 breeding bird species there are eight owls: Tyto alba, Glaucidium passerinum, Athene noctua, Aegolius funiereus, Otus scops, Asio otus, Strix aluco, Bubo bubo. Most importantly, the atlas highlights the profound changes that have taken place in the Swiss avifauna over the past 20 to 60 years. This comprehensive reference book provides an important foundation for the protection and conservation of native birds and their habitats.
Now the whole content of the book is available free on internet in German, French, Italian and English.
Click here for full text article»
Sieradzki, A and Mikkola, H. 2020. A Review of European Owls as Predators of Bats. In (Ed. Mikkola, H.) Owls. IntechOpen.
In this paper, we examine the ecological relationships between owls and bats and see if the larger owl species take larger bats as they tend to do with other prey. We conducted a literature review examining bats as prey in the diets of
European owls. The literature examined was published between 1886 and 2018 and covered the ecological timeframe of the Pleistocene to current day. A total of 1680 publications were examined, and a synthesis of the findings is reported here. Utmost effort has been made to avoid duplication in the counting of the same bats mentioned in the review papers and/or multiple papers by the same author. The collection of the data was limited to Eurasia and one particular case study in North Africa (short-eared owl—Algeria). Owl predation on bats deserves future research because it may help contribute to our knowledge on bat biodiversity and distribution and possibly identify an additional risk for small populations of endangered bats.

Click here for full text article»
Submit your recent owl publications

To submit a research summary for inclusion in this e-newsletter, please send an email to that includes:

-Proper citation for the article (published in the last 12 months; publication need not be in English, but please translate the title into English if it is not already)
-Short English summary of the research (250 words or less) that includes basic results (similar to an abstract, but not the actual abstract so we avoid any copyright infringement)
-Link to the full-text article if it is available online at no charge
-Email address for the corresponding author

-A photo related to the article, if available (it could be of an owl, researcher, location--something to grab attention)

Subscription is free, and the International Owl Center does not earn any revenue by sharing this information. Click here to sign up for the newsletter and/or peruse past issues.
International Owl Center, 126 E Cedar St, PO Box 536, 55943, Houston, United States
You may unsubscribe or change your contact details at any time.