At the beginning of the 20th century, the little owl (Athene noctua) was one of the most common birds of prey in the Czech landscape. Today, it is on the brink of extinction. Over the past few decades, its population has plummeted by a staggering 94%, leaving only about 100 breeding pairs in the entire country. Scientists and enthusiasts from the Czech Society for Ornithology and the Institute of Vertebrate Biology of the Czech Academy of Sciences are working to save the species. In April and June 2024, we had a unique opportunity to take part in two field expeditions in search of the little owl with biologist Martin Šálek.
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We spotlighted the little owl and its plight in the first English issue of the official quarterly A / Magazine of the CAS:
Did you know that three villages in Hungary have more little owls than the entire Czech Republic? These findings come from a study by Martin Šálek’s team at the Institute of Vertebrate Biology of the CAS, recently published in The Journal of Raptor Research.
Written and prepared by: Leona Matušková, External Relations Division, CAO of the CAS Translated by: Tereza Novická, External Relations Division, CAO of the CAS Photo: Jana Plavec, External Relations Division, CAO of the CAS
The text and photos are released for use under the Creative Commons license.
This photo story takes us to northwestern Bohemia – a beautiful, rolling region in the Czech Republic with sparse settlements and scattered small farms. Despite its charm, it remains largely undiscovered by tourists. It is also one of the few remaining places in the country where little owls can still be found.
Our guide, Martin Šálek from the Institute of Vertebrate Biology of the Czech Academy of Sciences, has long dedicated his efforts to studying and protecting the little owl, also known as the owl of Minerva (or Athena).
The field expeditions occurred in two phases. In early April 2024, we set out for the countryside around Házmburk Castle to monitor the condition and survival of the owls after winter. The second trip, in June 2024, focused on assessing nesting success.
The April expedition begins with a briefing at the biologist’s caravan, which serves as his base during fieldwork. He often spends several consecutive days in the field.
Since owls are primarily active in the evening and at night, we set off at dusk. Our first stop is a farmstead just a few dozen meters from the caravan.
From the car, the biologist points out likely spots where we might encounter our first little owl of the evening. In the background, you can make out the silhouette of Házmburk Castle.
To attract the little owl, we use a speaker to play a recording of a male’s call. The hope is that a territorial male will appear to confront the supposed rival.
Night falls quickly. In the distance, we hear an owl’s call – but as Martin points out, it’s a Eurasian eagle-owl, not a little owl. With no sightings yet, it’s time to move to another village, as little owls today are most commonly found nesting within human settlements.
“I’ve been coming to Házmburk to study the little owl since around 2000. Back then, there were about twenty males here. By 2015, that number had dwindled to five at most. Today, it’s just a handful of individuals,” Martin says.
To monitor the owls, the biologist uses binoculars and a thermal imaging night-vision device, which offers a fascinating view of the nocturnal landscape. Over the course of the evening and night, we spot not only several little owls perched on trees and rooftops, but also roe deer in the fields, hedgehogs on the roads, and cats, mice, and rats moving through the villages.
For the past ten years, Martin has also been recording the calls of hooting males: “These recordings allow us to analyze the melody and other vocal characteristics, helping us distinguish individual little owls.”
At each site, we set up an ornithological mist net in order to capture an owl. I try to assist Martin with the setup, but it takes me a few attempts to feel useful. This image was taken through the night-vision thermal imaging device.
Near the mist net, we place a decoy – a model owl that Martin calls Franta.
And how do little owls react to Franta? “There are three types of males. The first I call the aggressors – they attack Franta directly and usually get caught quickly. The second type are the negotiators – they circle around the net, perch, hoot, and try to resolve the conflict peacefully, but in the end, they also get caught. And then there are the ignorers – these are the tough ones, as they simply don’t allow themselves to be lured into the net,” the biologist says with a smile.
We can hear and see a little owl nearby, but it is clearly one of the “ignorers” – a type of male that does not confront rivals directly. Even after an hour of coaxing, it does not get caught in the net, so we pack up and move to another site.
Finally! We catch our first little owl. For me and the photographer, it’s a first-time experience. We can’t get enough of the adorable owl, about the size of a collared dove. It’s smaller than we expected it to be, with piercing, inquisitive eyes.
I was able to hold the little owl and examine it up close. It surprised me how calm it was.
After the biologist measures, weighs, and takes a genetic sample from the owl, we release it back into the wild. We pack up our “Franta” decoys and move on.
We arrive at another village. Martin always knows exactly where to go. Thanks to previous monitoring, he is familiar with the little owls’ territories – they are loyal to their home sites. Within minutes, we spot one perched on an antenna. Will we be able to lure it into the mist net?
Success! Next comes the weighing, measuring, ring checking, and taking a feather sample for genetic analysis.
Compared to other owls, the little owl is relatively small and light. Males weigh around 180 grams, while females average about 220 grams.
The biologist carefully records all the data in his field log.
We begin searching for and capturing little owls around 7 PM and finish around 4 AM. Our final stop is a field beyond a village, where we wait for a long time. We can hear the owls in the distance and eventually see them, but capturing one proves difficult. It takes nearly an hour before we succeed.
By then, night is giving way to dawn, and exhaustion hits us hard. We make our way back to the caravan. The unusually warm April weather means we can sleep under the open sky.
Two months later, we return for another little owl expedition, this time to check nesting success and the condition of the young. We start at another caravan, about 30 kilometers southeast of the previous one.
Leading the expedition, Martin Šálek has a prearranged list of farmers and local residents, calling them one by one to coordinate our visits. Over the course of the day, we visit around ten different locations.
Little owls often seek out agricultural buildings such as barns, nesting in cavities or special “little owl boxes” installed by ornithologists in cooperation with the landowners.
At our very first stop, we find several owlets inside a nesting cavity.
The chicks need to be carefully removed from the nest and taken down for examination.
Next come the weighing, measuring, ringing, photographing, and taking genetic samples. Zuzana Kučerová from the Czech Society for Ornithology records the data in the field log.
Researchers collect one to three feathers from the birds for genetic analysis. This research has revealed that, in recent years, relatively frequent inbreeding has led to a decline in the genetic health of the already fragile little owl population in the Czech Republic.
Based on illustrations in a reference book on the little owl, ornithologists estimate this chick to be about 18 to 20 days old.
Age can also be determined by the appearance of the wings. This photo shows a freshly applied leg ring, engraved with a unique identification number and code, which allows researchers to track the birds’ movements and survival more precisely.
A baby little owl might not win any beauty contests – with its oversized feet, downy feathers, a grumpy expression – but in just a few weeks, it will transform into a striking bird with captivating, intelligent eyes.
The field log records information about the site, measurements and weight of the captured little owl chicks, and the numbers of their ID rings.
Last season, little owls occupied nearly 60 territories in northwestern Bohemia and raised at least 71 chicks.
However, despite the joy of each new hatchling, the harsh reality is that nine out of ten little owls don’t survive their first winter. Even adults face many dangers, from drowning in pools and wells to getting trapped in molasses tanks.
This is an owl pellet containing undigested food remains. Inside it you can find tiny bone fragments, fur from mice and voles, or beetle elytra. “We used to think, based on pellet analysis, that small mammals made up the majority of the little owl’s diet, but that’s not the case. Footage from nest box cameras clearly shows that insects and earthworms account for the overwhelming majority of prey brought into the nest,” says Martin. Invertebrate remains are difficult to detect in pellets, as an earthworm, for instance, leaves behind only barely visible bristles.
You can easily recognize the “little owl team” when it’s out in the field. They all wear T-shirts featuring a little owl. Another giveaway is the one-liner on their car: “Vymírám, a to nesýčkuji. [I’m going extinct, and I’m not just being an alarmist]. The little owl. Help us save it,” accompanied by the logos of the Czech Society for Ornithology and the Institute of Vertebrate Biology of the CAS.
We enter another farm complex. We’re taking a ladder with us which we’ll need to access the nest box.
Last spring, the ornithologists and farmers installed twenty new nest boxes. In some of them, they discovered freshly hatched chicks already just a few weeks later.
The nest boxes are secured against martens, cats, and other predators. Ornithologists install them almost exclusively in human settlements, especially on farms, as the little owl has moved from open agricultural landscapes into these areas.
One of the nest boxes is located inside a barn. As the ornithologists find out, the female little owl is still incubating the eggs. (Two weeks later, the team returns to ring six chicks).
We move on to the next site.
And we get lucky! There are chicks in this box! Martin carefully removes them one by one to measure, weigh, and ring them.
These are probably the youngest little owl chicks we’ve come across today. They are only a few days old.
Ornithologists work closely with local residents to protect little owls. They inform them about risks to the young, such as free-roaming dogs and cats or various human-made traps like uncovered water barrels and upright pipes.
We weigh the baby little owls using a digital kitchen scale. This chick weighs only about one hundred grams.
An adult and a chick little owl can both fit in the palm of a man.
We move on again, this time to a larger agricultural cooperative.
There, we discover another sizable brood of owlets.
And the process repeats: weight, measurements, ring, and comparison with the reference book. We record the data and off we go.
At the next site, what we find in the nest box is neither chicks nor a little owl. Instead, a barn owl has taken up residence!
The barn owl is larger than the little owl. Its body length ranges from 33 to 39 centimeters, with a wingspan of 80 to 95 centimeters.
Its identification ring is slightly loose – it needs to be tightened to prevent it from slipping off.
You can recognize a barn owl by its distinctive heart-shaped facial disk.
We spend the entire day traveling through northwestern Bohemia, in the region of the former Sudetenland. Some homesteads here have been abandoned for decades, and the crumbling buildings with overgrown vegetation provide shelter for insects, birds, and small mammals.
In one nest box, we find a tiny chick of the little owl, only a few days old – it is still blind.
At another site, we find older chicks. As usual, we proceed with weighing and measuring their body and wingspan.
By examining the size and shape of the head, we can determine whether it is a male or a female little owl.
Martin Šálek is thrilled by every little owl he finds: “Certain areas of the Czech Republic are unfortunately ‘little owl deserts,’ such as South Bohemia. In the Pilsen region, there are only seven remaining pairs, while South and Southeast Moravia have around fifteen pairs.”
It would be a great loss if the little owl – once a common sight in our country – disappeared for good. Ongoing research, population monitoring, and a range of conservation measures, which scientists from the Czech Academy of Sciences have been involved in for over 25 years, aim to reverse this negative trend.
The goal of the rescue program, launched in 2022, is to stabilize a viable little owl population. Ideally, the species’ numbers in the Czech Republic should increase to at least a thousand breeding pairs, with the aim to connect isolated pockets of their current distribution. Let’s hope it works! You can find more information on the website of the Czech Society for Ornithology: www.birdlife.cz/projekt-zachranme-sycka/.
The primary mission of the CAS is to conduct research in a broad spectrum of natural, technical and social sciences as well as humanities. This research aims to advance progress of scientific knowledge at the international level, considering, however, the specific needs of the Czech society and the national culture.
President of the CAS
Prof. Eva Zažímalová has started her second term of office in May 2021. She is a respected scientist, and a Professor of Plant Anatomy and Physiology.
The text and photos are released for use under the Creative Commons license.
