Yeah installing the nest boxes as far away as possible from the road will definitely help in reducing the mortality.

But you will also have to consider the home range for these owls and also how far they can fly, for example in case of resources scarcity. Also consider the shade provided by the trees so that the owls are protected during bad weather conditions like rains or snowfall(where ever applicable), because on the roadside there is very little shade and there it is very difficult for the owls to hunt in rains, same should not be the case here.

Coming back to the next boxes installation;

If you are talking about chicks then its a good solution I think, but for juveniles who have recently started flying, for them it probably will make little difference as the juveniles are very curious and their curiosity might pose a problem in this case, as they will be eager to explore. For adults it won't be much of an issue but again that depends on the availability of food and other resources in the areas where these nest boxes are installed. Like for example as owls mostly feed on rodents, and rodents live mainly in grasslands, so the nest site should be such that its shaded well by the trees but also has some open grassland patches nearby.

I just expressed my views here, I am not a conservation biologist and have never worked for any, but as an ecologist these are my views. Hope it will be of at least a tiny use for you.

And also I think you already would have taken into account all these suggestions said above.

Cheers!!

What about using playbacks of owls near the road edges, possibly to discourage them (over longer time scales) from breeding in the area? Of course, this must be balanced with the fact that owls respond to playbacks of conspecifics. What about a playback of a larger-bodied competitor (another large owl, for instance)? Another possibility is playing masking tones at dawn and dusk to directly interfere with their ability to communicate. Over time, this should force owls to move away from roads in order to hear potential mates, etc. Just some random ideas. The nest box idea is good, but I think it would be good to complement this cavity supplementation with some aversive stimuli at all seasons (i.e. not only the breeding season). Because many (all?) owls are secondary cavity nesters, maybe you could also remove trees with cavities from the areas near roads immediately prior to the breeding season (when owls might be prospecting for territories)?

Thanks for answers, I am thinking about the nestboxes, minimize the mortality of juveniles - because these birds are most endangered - the results from ringing in Czech republic and Slovakia (by tawny owl) showed that big part of dead birds was found within 1 km from the nest. I think this is because the juveniles are inexperienced and risk of death is higher for them (especially during dispersal). The adults stay in the territory for all year, the risk of collision is lower by them.

It is interesting idea - discourage owls from the roads. I have same idea, but I am still thinking about, if it is ethical. Do you have some experiences with this reason?

Considering the ethics is always important, of course. However, the primary goal is to prevent mortality of owls, which in my opinion outweighs any potential (and I emphasize the word "potential") ethical issues associated with acoustic playbacks. Most of the concern raised about the use of playbacks comes from a relatively small literature on the impacts of simulated intrusion on the behavior and endocrine response of birds. Much of the work that opponents of playbacks cite as evidence of harmful effects comes from work done in the laboratory where I did completed my Ph.D. None of that work examined long-term effects of playbacks or attempted to suggest that transient increase in hormone levels (e.g. testosterone) would have longer term impacts. Secondly, opponents of playbacks generalize the results of small-scale studies and use the results to suggest that most, if not all, acoustic playbacks to every bird species is unethical. This may be the case for an endangered species that responds in some way that interrupts breeding or places the individual directly in harm's way. Every practitioner has anecdotes that suggest that playbacks are harmful or not. So, I agree that it would be good to first examine how some owls would respond to playbacks of conspecifics and heterospecifics. If anything, doing a pilot study would be ethical. If it worked and was implemented in such a way to decrease mortality of owls around roads, I would argue that playbacks would be highly ethical, if "ethical" is defined as doing what is best for the species.

Also, kindly look at the Global Owl Project (GLOW). The official website is:

http://www.globalowlproject.com

and contact David H. Johnson, Director-Global Owl Project. His email is: [email protected]

On the other hand, you can ask something with sent to all policy to:

[email protected]

I contacted GLOW - but with other question. But here (in researchgate) are many researchers and conservation biologists and I would like to know more points of view from more people.

I know that owls frequent roads to hunt easily obtainable rodents that feed next to the road. Also busy roads fragmenting owl habitat can be also a mortality factor, especially for juveniles either searching for an easy prey, or dispersing from nesting site. We have several incidents, especially regarding barn owls but also Little owls and Long-eared owls as road kills. we also have nightjars being hit by traffic when searching for moths at night.

You can put your nesting boxes as far as possible from busy rods, but if habitat is otherwise suitable, birds will come...

Unfortunately is a mortality factor that we must live with in this world...