This study shows the phenological aspects, the dynamics and distribution of Asio otus colonies in Botoșani county, as well as the anthropic [622008]

Abstract

This study shows the phenological aspects, the dynamics and distribution of Asio otus colonies in Botoșani county, as well as the anthropic
influence over the long -eared owls in the surveyed zone. The observations took place over the period of No vember through December
2018 and January through February 2019, by moving around in 9 settlements in Botoșani county, including the municipality of B otoșani.
9 colonies were identified having a total of 340 Asio otus specimens, and in one of the colonies t here were found two Asio flammeus
individuals. The maximum number of specimens is reached in the months of January and February, and the minimum number in the
months of November and December. The grouping degree of the Asio otus individuals is influenced b y the climatic conditions, more
specifically by the temperatures and rainfall/ snowfall. Moreover , it has been observed that there is an inverse correlation between the
long-eared owls and temperature. Thus, when the temperatures tend to fall, the grouping degree of the colonies register significant growth.
The preferred species of trees are gymnosperms (69%), though the owls were found on angiosperms as well (31%). The preference for
the coniferous species increases along with the drop in temperatures and the increase in rainfall or snowfall, as these types of trees offer
better protection against the weather conditions.

Key Words : Asio otus , weather conditions, winter colonies, phenology, tree selection

Introduction

Depending on different factors ex erted on an ecosystem, each taxonomical group has the capacity to respond through specific
means of adopting different strategies towards keeping the integrity of the group. This way, some bird species adopt a grouped
distribution with the goal of creating a unitary population, which helps them be better protected against predators, weather
conditions and the finding of food, all objectives being made easier this way. A relevant example of such an advantage that
grouping gives is found in some strigiform sp ecies, which, in the cold season, choose to abandon the solitary and territorial
behavior they have during the reproduction period, and opt to form colonies in different places. (GRYZ et KRAUZE -GRYZ,
2015) .
Such a significant example of this behavior is th e long -eared owl, Asio otus (Strigidae, Strigiformes L.) spread throughout:
Europe, North -West Africa, Asia and North America (Marks and coll. 1994, Moga and coll., 2005). The populations from
the northern parts of its range are migratory, and those from t he southern and western are sedentary. (Crampet Simmons,
1985, Kucherenko et Kalinovsky, 2018 . Asio otus constitutes one of the most wide -spread strigiform species in Romania in
particular, and in Central Europe in general. (TOMIALOJC et STAWARCZYK,2003; KOWALSKI et al. 2007; KÖNIG et
WEICK 2008, GRYZ and Dagny KRAUZE -GRYZ, 2015) . Typical of the long -eared owl is the way they form large colonies
during winters, in diverse areas, where they can find a stable source of food, protecting themselves more easily against
weather conditions and potential predators. (Moga and coll., 2005) . Among their favorite places there are the urban and
suburban areas, an aspect which facilitates the observation of the species. (Cramp 1985, GALLI et al, 2015; LÖVY et
RIEGERT, 20 13)
Throughout the cold season, in the Asio otus colonies, there can be spotted also individuals of Asio flammeus , which appear
as visitors due to the fact that this species’ presence in Romania is rare in contrast to that of the long -eared owl. (PappetSá ndor
2007; Calladineet al. 2012, Cramp 1985, Schmidt, 1959, Ionescu et al, 2017)
It is known that the climate change which affects the whole planet, and the excessive urbanization, influence the behavior
and phenology of birds (Møller et al 2010 ). The majo rity of studies done on Asio otus colonies (Laiu et al, 2003; Nistreanu
and Postolachi, 2011; Chiba el al, 2005) are focused on the regime and trophic preference of the long -eared owls and short –
eared owls and very few study aspects like the dynamics of in dividuals in colonies. In this context, we decided that our focus
to be centered on phenological aspects, the dynamics of populations and the anthropic influence over the species of Asio otus
and Asio flammeus. (Kucherenko et Kalinovsky, 2018) This represe nt the first study of its type in the county of Botoșani ,
which besides all the phenological and populations dynamics information, brings also data about the distribution of the
species in the area.

Study area
Our study was conducted in the north of the region of Moldova, more specifically in Bot osani county (47 ° 50′N 26 ° 49′E).
Located on the old Platform of Moldova, Botoșani county constitutes 2.1% of the surface of Romania, being spread over
4965 km2. (Mititelu and Chifu, 1994; Varvara and Apostol, 2008) As regards this relief, it is not extr emely varied, the
predominant forms being: plains, plateaus and hills. Of the total area, agricultural lands account for the most part 82%,
followed by natural grasslands 14% and forested lands that account for only 11%. (Mititelu et Chifu, 1994) The agric ultural
Figure 1 . Map with settlements in which Asio otus colonies were id entified

lands and the natural grasslands are important areas for the forest logs, they provide a valuable food resource for them. At
the same time, forested areas and parks are important nesting areas for the colonies of Asio otus . The aspects mentioned ar e
also found in the distribution of the studied logs colonies, these being identified in the localities surrounded by meadows and
agricultural lands. Moreover, the colonies were located near parks, forests, where nests of Corvus frugilegus were found,
supp orting the nesting of the species.

Materials and methods
The observations were collected throughout the period of November – December 2018 and January – February 2019, when
we conducted trips in 8 settlements in Botoșani county, as well as in the municipa lity of Botoșani . For correctly identifying
the points of interest and for an orderly gathering of data, the exploited methods were: fixed -point iteration, trail method, the
counting of all individuals and taking picture to each one of them. The identifica tion of the colonies was accomplished by
talking with locals (by showing them pictures), as well as the surveying of the areas which seemed favorable for the Asio
otus colonies (e.g.: areas with old buildings, spa ces surrounded with gymnosperms). After pin pointing the colonies, we
collected information about the number of individuals, the influence of the anthropic factor (graded from 1 to 7), tree species
they occupied, as well as the dynamic of the populations i n relation with weather conditions. At the same time there has been
registered, for each spot, the corresponding temperature, to establish if there’s a correlation between weather conditions an d
the type of tree chosen by the individuals. Moreover, after t he field trips we observed that the anthrop ic factor influence is
significant at the level of Asio otus populations, which is why we wished to grade this impact by giving grades from 1 to 7,
to evaluate the state in which the colonies are now and to foresh adow their evolution in the future. (fig.2) Grade 1 describes
the area in which the presence of man does not influence at all the colonies of Asio otus, these being located in secluded
areas. (e.g: Știubieni ) Grade 2 represents a space in which the Asio ot us individuals are phonically disturbed by the passing
cars in their vicinity. (e.g: Dorohoi, Avrămeni, Botoșani, și Roma ) Bucecea is the settlement registered with grade 3, due to
the fact that the Asio otus colony is disturbed phonically from the cars, s hops and pubs nearby, as well as by the lig ht emitted
from the surrounding buildings. In the settlement of Corlăteni the colony of Asio otus was disturbed and cast off by the locals
because of the owl pellets that piled up in their yards, thus grading the impact in this case with a 4 . In Dobârceni , the grade
given was 5, due to the fact that to the disturbance of the long -eared owls, fireworks used on hildays contributed as well.
Grade 6 illustrates activities during the winter hildays, such as: placing of a stage near the colonies, installing of Ch ristmas
lights near the owls, the carols which were broadcast during the day in from of the Săveni town hall, the place around which
the long -eared owls were located. The 7th grade indicates a decline in the population of owls, the death of some individuals
from diverse reasons, a situation which thankfully was not registered in any of these loca tions.

01234567Evaluation of anthropic factor
Figure 2 . Grading of the anthropic effect over the Asio otus colonies identified in Botoșani county

Results and discussions

There were identified 9 colonies with a total of 340 specimens. The maximum number of a colony was of 51 individuals and
the minimum of 28, with an approximated average of 38 specimens. (table 1)

Concerning the dynamics, the highest number of individuals was observed in the months of January and February 2019 (fig.
3). It was noted that, once the temperatures fell, the number of individuals in colonies registered a n increase, fact which
proves that this species’ organization during the cold season is influenced by the weather conditions. According to specialty
literature, in the interval of 2014 -2015, the maximum number of individuals in the southern part of Romania was reached in
the months of February and November. (Mestecăneanu et Gava, 2015 ) In other countries, the fluctuations are more different,
as in Italy (Pirovano et al, 2000) the peak is registered in the month of December, in Russia (Sharikov et al, 2013) the peak Time of observation Settlement Number of individuals Temperature
21.11.2018 Săveni 30 -1⁰
21.11.2018 Avrămeni 32 -2⁰
27.12.2018 Dobârceni 30 1⁰
1.01.2019 Dorohoi 28 -1⁰
1.01.2019 Săveni 51 1⁰
12.02.2019 Dorohoi 49 -2⁰
13.02.2019 Bucecea 30 -1⁰
13.02.2019 Botoșani 48 0⁰
13.02.2019 Știubieni 30 0⁰
16.02.2019 Corlăteni 40 -1⁰
16.02.2019 Roma 30 0⁰
Table 1. Frequenc y of the number of individuals, depending on the period in which the observati ons took place and on
temperature fluctuation

is reached in the months of December and Janu ary and in Ukraine, more specifically in the Crimea ( Kucherenko et
Kalinovsky, 2018) the maximum number is reached in November and December. Confronting all this data, the dynamics of
the populations we observed is closest to that of Russia. It is observed that, at the same time, the dynamic of Asio otus
colonies, which can differ even at the level of this country, the main reason is being represented especially by the different
weather conditions.

The places in which the Asio otus colonies were id entified are surrounded by different old buildings, blocks, among their
favorite places being: public parks (10%), block gardens (20%), private areas (20%), areas in front of public institutions
buildings (30%) and areas next to the road (20%) . The specie s occupied by Asio otus individuals are: Betula pendula, Picea
abies, Fagus sylvatica, Thuja occidentalis, Fraximus excelsior, Salix alba (fig 4) , the highest preference being for the
coniferous species. (Pirovano et al, 2009)

050100150200250Number of Asio otus individuals
Months in which observations were conducted
Figure 3 . Frequency of the number of individuals depending on the month of the observations November December January February

Therewith, the individua ls’ preference for a certain type of tree was also observed, data being collected referring to the
number of specime ns of Asio otus occupying each tree species (table 2). Most individuals were observed on the species of
Picea abies , though they were presen t on other species too. It was observ ed that in Asio otus colonies the tree species they
choose is influenced by the weather conditions as well. This fact was observed in Săveni and Dorohoi , places in which we
conducted trips in different periods of time. Thus, once with the decrease in temperatures or the increase in intensity of
rainfall and snowfall the Asio otus individuals opted to group in larger numbers on species of gymnosperms, these offering a
better protection against the weather. In days in which showers didn’t occur, the individuals had random groupings, them
being found on angiosperms as well as gymnosperms.

Settlement Tree species selected and their number Number of Asio otus
individuals
Dorohoi Salix alba (2) 18
Fraxinus excelsior (1) 31
Săveni Picea abies (4) 32
Thuja occidentalis (3) 12
Fagus sylvatica (1) 4
Betula pendula (2) 3
Avrămeni Picea abies (3) 32
Dobârceni Picea abies (4) 30
Bucecea Picea abies (2) 30
Botoșani Picea abies (4) 48
Știubieni Picea abies (4) 30
Corlăte ni Picea abies (7) 40
Roma Picea abies (6) 30
Picea abies
61%
Salix alba
7%Fraxinus excelsior
8%Thuja occidentalis
8%Fagus sylvatica
8%Betula pendula
8%Table 2. Distribution of Asio otus individuals depending on the tree species for each point of observation
Figure 4. Preference of indivi duals of Asio otus for tree species

The direction of the air currents was another parameter recorded during the study. It has been observed that the wind does
not change the dynamics or degree of grouping of individuals in a colony. More over, in most cases, the colonies of Asio otus
were located in such a way that the buildings around them provided protection against the climatic conditions (fig. 5)
(Kucherenko and Kalinovsky, 2018)

In one of the colonies of Asio otus, two specimens of A sio flammeus (Știubieni ) were identified, a species with few reports
in the region of Moldova. At the same time, they were also surprised among the colonies and individuals of Streptopelia
decaocto, Corvus monedula and Corvus frugilegus. Due to the larger number of individuals in the city of Săveni, we collected
the pellets to observe the colony's preference for a certain trophic regime. Among the identified species are:

Throughout the study, no injured or dead owls were identified, even though the anthropogenic impact exerts significant
pressure on some colonies. (Kucherenko et Kalinovsky, 2018) We point out that habitat destruction and disturbance of this
species can have a major impact on the future .

Conclusions

1. In the period of November – December 2018 and January – February 2019, there were 9 Asio otus colonies identified,
with a total of 340 specimens in the county of Botoșani .
2. In Botoșani county the ma ximum number of Asio otu s individuals is reached in the months of January and February,
and the min imum number is observed in the months of November and December. 20%
30%
20%20%10%
Grădinile blocurilor
Curtea instituțiilor publice
Spații private
Pe marginea șoselelor
ParcuriPrivate areas
Border of the streets
Figure 5. Preferred areas by Asio otus individuals
Block gardens
Public institutions yards
Parks

3. The dynamic of Asio otus colonies is influenced by the cli mate conditions, more preci sely by temp eratures and
rainfal l/ snowfall, these being a cause of the grouping degree of individuals.
4. The prefe rred tree species by the m are represented by gymnosperms , these offering an enhanced protection against
weather cond itions.
5. The pursuance and the effectuation of the census on the species re presents an important element due to the fact that
the anthropic impact affects the Asio otus colonies more and more.
6. Global warming is getting stronge r, this being a factor which de stroys habitats and limits food resources for more
and more species, in cluding the species of Asio otus and Asio flammeus.

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