SOME OBSERVATIONS REGARDING THE DEPARTURE OF THE TAWNY OWL (STRIX ALUCO) FROM THE DAYTIME ROOST DEPENDING ON TIME AND CERTAIN ENVIRONMENTAL CONDITIONS

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1 Analele Științifice ale Universității Alexandru Ioan Cuza din Iași, s. Biologie animală, Tom LVIII, 2012 SOME OBSERVATIONS REGARDING THE DEPARTURE OF THE TAWNY OWL (STRIX ALUCO) FROM THE DAYTIME ROOST DEPENDING ON TIME AND CERTAIN ENVIRONMENTAL CONDITIONS Adrian MESTECĂNEANU 1 and Florin MESTECĂNEANU 2 1 Argeș County Museum, Armand Călinescu, 44, , Pitești, Argeș, Romania, mestecaneanua@yahoo.com 2 Dârmănești, , Argeș, Romania, mestecaneanuf@yahoo.com Abstract. Based on 192 observations performed on a tawny owl (Strix aluco) in Dârmănești locality in 1999, 2004, 2005 and 2006, the authors analyze the influence of the time and the environment conditions on its departure from the daytime roost (an unused chimney). The most of observations were done in the hiemal season, when the studied individual usually left the shelter between 17:10 and 17:19. The time difference between the sunset and the mean of the departures from the shelter varied between 24 minutes (in September) and 40 minutes (in December). It was stated that the environmental conditions influenced the departure from the daytime roost; generally, the bird left the chimney few minutes later (when the temperature of the air was below 0 0 C, the sky coverage with clouds was below 50%, the sky was clear or covered with superior clouds, the wind blew, the Moon illuminated the landscape or the snow cover existed on soil) than in the other cases. Keywords: tawny owl (Strix aluco), daytime roost, time, environmental conditions. Rezumat. Câteva observații privind plecarea huhurezul mic (Strix aluco) din adăpostul de peste zi în funcție de timp și unele condiții de mediu. Pe baza a 192 de observații realizate pe un huhurez mic (Strix aluco) în localitatea Dârmănești, în anii 1999, 2004, 2005 și 2006, autorii analizează influența timpului și a condițiilor de mediu asupra plecării acestuia din adăpostul de peste zi (un coș nefolosit de fum). Majoritatea observațiilor au fost făcute în sezonul hiemal, atunci când exemplarul studiat a plecat din adăpost de cele mai multe ori în intervalul de timp 17:10 17:19. Diferența de timp dintre apusul Soarelui și media plecării din adăpost a variat între 24 de minute (în septembrie) și 40 de minute (in decembrie). S-a constatat că condițiile de mediu au influențat plecarea de la locul de odihnă, în general, pasărea părăsindu-l cu câteva minute mai târziu (atunci când temperatura aerului a fost sub 0 0 C, nebulozitatea atmosferică a fost sub 50%, cerul a fost senin ori acoperit cu nori superiori, vântul a bătut, Luna a luminat peisajul sau pe sol a existat un strat de zăpadă) decât în celelalte cazuri. Cuvinte cheie: huhurez mic (Strix aluco), timp, loc de odihnă de peste zi, condiții de mediu. Introduction The Tawny Owl (Strix aluco) is a medium sized, compact owl. Its mottled, finely streaked and vermiculated dark plumage have a ground colour variable from rufous-brown to greyish-brown. It lives in forests, parklands, wooded farmlands, preferring old broadleaf trees. Usually found near humans in gardens and towns where hunts rodents around farmhouses and it even roosts on buildings (Svensson et al., 2009). Although it prefers to breed in tree cavities, it is extremely adaptable and it will use a wide range of alternative nest sites, including constructions (Hagemeijer & Blair, 1997). It is spread in Europe (generally except its northern part), Asia (parts of Russia, Asia Minor, Middle East and Himalayas) and North Africa (Morocco, Tunisia and

Adrian Mestecăneanu & Florin Mestecăneanu Mauritania), (König & Weick, 2008). In Romania, it is frequent and largely spread in all vast forests from the plain to the mountain (Munteanu et al., 2002).

In Romania, the most studies about the tawny owl were conducted mainly on its diet (Popescu & Savu, 1981; Savu, 1982; Petrescu, 1992; Benedek, 2004).

2 Adrian Mestecăneanu & Florin Mestecăneanu Mauritania), (König & Weick, 2008). In Romania, it is frequent and largely spread in all vast forests from the plain to the mountain (Munteanu et al., 2002). Regarding the departure from the daytime roost, we do not know if researches have been performed. In Romania, the most studies about the tawny owl were conducted mainly on its diet (Popescu & Savu, 1981; Savu, 1982; Petrescu, 1992; Benedek, 2004). Material and Methods The researches were performed in Dârmănești village from the Argeș County. Dârmănești village belongs to the locality with the same name. It is situated at ca. 350 m height on the Râul Doamnei Valley. Eastwards there is the hill (541 m maximum height) and westwards there is the Râul Doamnei Meadow ( m height). The built-up areas are disposed along the main road, Pitești-Nucșoara, and along the secondary ways, too (Fig. 1). Figure 1. The map with the location of Dârmăneşti village (marked with oval contour), (modified by Barco & Nedelcu, 1974). Figure 2. The satellite image of the Dârmăneşti village (in format Google Earth). The orchards and the gardens are distributed on the sides of the built-up areas and also in its inner area (Fig. 2). They are cultivated with plum trees (Prunus domestica), apple trees (Malus pumila), pear trees (Pyrus communis), walnuts (Juglans regia) etc. and various vegetables (Brassica oleracea, Capsicum annuum, Solanum lycopersicum, Solanum tuberosum, Phaseolus vulgaris, Allium cepa, Daucus carota, etc.), cereals and fodder plants (Zea mays, Trifolium pratense, Medicago sativa, etc.). The hill is covered with plum and apple orchards, near the village, and with deciduous

Analele Științifice ale Universității Alexandru Ioan Cuza din Iași, s. Biologie animală, Tom LVIII, 2012 forests (Fagus sylvatica, Carpinus betulus and Quercus sp.), in the rest.

At the moment of observations the tawny owl occupied one unused chimney of the authors house. This is built of burnt bricks and has approximately 0.5 m width, 0.8 m length and 1.5 m height.

February 1999 21 November 2005 5 January 2006 Figure 3. The tawny owl at the daytime roost (at three different dates).

3 Analele Științifice ale Universității Alexandru Ioan Cuza din Iași, s. Biologie animală, Tom LVIII, 2012 forests (Fagus sylvatica, Carpinus betulus and Quercus sp.), in the rest. The floodplain is mainly cultivated with cereals and fodder plants (Triticum durum, Zea mays, Trifolium pratense, Medicago sativa, etc.). At the moment of observations the tawny owl occupied one unused chimney of the authors house. This is built of burnt bricks and has approximately 0.5 m width, 0.8 m length and 1.5 m height. Inside there are two ways for the flue evacuation. Its roof creates a shelter with 14 cm width and cm height. The accesses are on North South direction (Fig. 3). February November January 2006 Figure 3. The tawny owl at the daytime roost (at three different dates). The observations were done in the evening with a 10*50 binocular and with the naked eye. We registered for each observation the date, time (using the standard time), temperature of the air (measured at two meter height, in 0 C), atmospheric nebulosity (the clouds coverage of the sky, on 1 10 scale), type of the clouds (who gave the level of the clouds), magnitude of Moon (found with Stellarium astronomical software with the mention that when the Moon was not present on sky or when nebulosity was between 9 and 10, we considered the magnitude 0), wind intensity (expressed on the Beaufort scale), direction of displacement after the departure of the daytime shelter, and other details, by case. There were 4 records in January 1999, 20 records in December 2004, 121 records in 2005 (8 in January, 6 in February, 19 in March, 14 in April, 9 in May, 6 in June, 8 in July, 5 in August, 5 in September, 8 in October, 15 in November and 18 in December) and 47 records in 2006 (17 in January, 10 in February, 6 in March, 2 in June, 3 in July, 5 in August and 4 in September). Results and Discussion It is known that the tawny owl roosts by day among dense foliage, on a branch close to the trunk, in a natural hole in a tree or a rock, in a hole or a crevice of wall, in the attic of larger building, in barns or sheds, inside church towers, sometimes in a house chimney (König & Weick, 2009). In our case, the observed individual was a male. Mainly in the morning, the bird used to sunbathe on the South side of the chimney. If it were undisturbed, it spent all day at the South or North entrance, swearing on the camouflage colour of its plumage. In an opposite situation (human disturbance or attack of birds), it climbs down on the lower wall that divides the two ways for the flue evacuation. The records were not equally distributed because of the habit of the bird from the prevernal autumnal period to spend daytime, in certain days, in other places; also, we could not make observations every evening. The most of observations were effectuated in

4 16:00-16:59 17:00-17:59 18:00-18:59 19:00-19:59 20:00-20:59 21:00-21:59 22:00-22: January February March April May June July August September October November December Prevernal Vernal Aestival Serotinal Autumnal Hiemal The whole period Adrian Mestecăneanu & Florin Mestecăneanu November and January (ca. 35%). In June and October was the least number of observations (ca. 8%). Depending on the ecological seasons, of all 192 observations registered in the four years of observations, in the hiemal season were recorded 51.04% and from vernal to autumnal only 28.64% (Table 1). The last record was on 24 September 2006 and until now no individual has arrived into the shelter of the chimney, despite of the fact that in the area there are probably still one or two pairs (visually or auditive determined). The reason is the accommodation in the vicinity of one family of stone marten (Martes foina) that visits all unused chimneys, jumping from one building to another. According to the lapse of time, regarding the entire period, we stated that 44.27% of observations was noted between 17:00 and 17:59. The earliest observation was registered at 16:57 on 6 December 2004 and the latest observation was registered at 20:45 on 8 July 2005 (Fig. 4). Regarding the hiemal season, the earliest observation was registered at 16:57 on 6 December 2004 and the latest observation was registered at 18:32 on 27 February The most of the leavings were recorded between 17:10 and 17:19 (33.67%), in the rest laps of the time (every 10 minutes) their percentage being under 15 % (Fig. 5). Table 1. The distributions of the observations by months, ecological seasons and overall. Period Observations Percentages Figure 4. The distribution (%) of the observations according to the lapse of time (every hour) during the whole year

5 0:39 0:29 0:29 0:26 0:27 0:32 0:26 0:28 0:24 0:25 0:33 0:40 0:20 0:25 0:24 0:31 0:30 0:48 0:12 0:05 0:03 0:08 0:10 0:06 0:11 0:15 0:13 0:05 0:06 0:12 0:13 0:15 0:09 0:01 0:03 0:06 0:05 0:01 0:03 0:05 0:06 0:07 17:39 18:12 18:50 19:26 20:03 20:34 20:23 19:49 18:50 17:56 17:20 17:14 19:03 20:11 20:26 19:40 18:14 17:31 18:26 17:00 17:43 18:21 19:00 19: :57 19:21 18:26 17:31 16:47 16:34 18:43 19: :09 17:44 16:43 18:14 January February March April May June July August September October November December Prevernal Vernal Aestival Serotinal Autumnal Hiemal The whole period 16:50-16:59 17:00-17:09 17:10-17:19 17:20-17:29 17:30-17:39 17:40-17:49 17:50-17:59 18:00-18:09 18:10-18:19 18:20-18:29 18:30-18:39 Analele Științifice ale Universității Alexandru Ioan Cuza din Iași, s. Biologie animală, Tom LVIII, Figure 5. The distribution (%) of the observations according to the lapse of time (from 10 to 10 minutes) during the hiemal season. The mean of the departures was between 16:34, in December and 2, in June. Depending on the ecological seasons, the mean varied between 16:43, in hiemal, and 2, in the aestival season. For all year, the mean was 18:14. The difference from the sunset time and the mean of the time of departure from the shelter was between 24 minutes (in September) and 40 minutes (in December). A big difference was in January, too (39 minutes). Considering the ecological seasons, this parameter varied between 20 minutes (in prevernal) and 48 minutes (in hiemal) but the data must not be considered certain because of the unequally distributed records. For all year, this difference was 12 minutes. The sunset was calculated for the day of the middle of each period: 15 for every month, 31 March, 23 May, 7 July, 23 August, 8 October, and 30 December for each ecological season and 22 September the Equinox, for the whole year (Table 2). In this goal, we used the free software, Stellarium , the geographic coordinates for Dârmanești village being N and E. Table 2. The sunset and the times of the departure from the refuge (h:mm). Period Sunset Mean of the times of departure Standard Error Confidence Level (95.0%) Difference between the sunset and the mean of the departures

6 Adrian Mestecăneanu & Florin Mestecăneanu Depending on the environmental conditions (that can influence the behavior of the bird) registered in December and in the hiemal season at the moment of departure from the shelter we stated that when low temperatures of the air are recorded on average the bird leaves later than when higher temperatures are recorded (Table 3). For the clouds coverage of the sky between 0 and 5, the means of departures were bigger than the means for the clouds coverage of the sky between 6 and 10. For the level of clouds, when the clouds were at the inferior or medium level bird leaves on average earlier than when the clouds were at superior level or when the sky was clear. In the hiemal season the wind intensity determined the delay of the departures when its intensity was 1 (in December, the wind had always intensity 0). Regarding the magnitude of the Moon, when the Moon was not present on the sky or when the sky was covered by clouds almost in totality (nebulosity 9 10) the bird departures earlier than in the rest of the cases. The presence of the snow cover generally produced a delay of the departures in both cases. We also showed the situation for the whole period, although this is less conclusive. The direction of displacement after the departure from the daytime roost varied depending on month and ecological season (Table 4). So, the most times the bird left in January to South, in February to South-West, in March, April, May and June to North, in July to North and South, in August and September to North, in October to North-East, in November to North and North-East, and in December to North. According to the ecological seasons, the most times the bird left to North (in the autumnal season to North-East, too). If we take into consideration the whole period, the most times the bird left to North; in smaller percentages it left to South and to North-East. We notice that there are buildings towards North and towards South. Behind of them there are stalls for animals and gardens and orchards. Beyond them, there are the hill (to East) and the meadow of the Râul Doamnei (to West). Towards North-East, a gill links the village and the orchards and the forests from the eastern hill. Table 3. The variation of the mean of the departure from the daytime roost depending on the environmental conditions. Period December Hiemal The whole period Parameter Number of Number of Number of Mean Mean observations observations observations Mean Intervals of : : :53 temperatures : : :36 Intervals of : : :38 nebulosity : : :14 Inferior or Level of medium clouds 31 17: : :23 clouds Superior clouds or clear sky 7 17: : :36 Wind : : :28 intensity >= : :05 Magnitude of : : :21 the Moon : : :41 Snow depth : : :29 (cm) >0 1 17: : :

7 Direction of move January February March April May June July August September October November December Prevernal Vernal Aestival Serotinal Autumnal Hiemal The whole period Analele Științifice ale Universității Alexandru Ioan Cuza din Iași, s. Biologie animală, Tom LVIII, 2012 Table 4. The direction of displacement after the departure from the daytime roost. N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Conclusions The departure of the tawny owl (Strix aluco) from the daytime roost depended on time, more exactly, at sunset, the time difference between it and the mean of the departures from the shelter varying between 24 minutes (in September) and 40 minutes (in December). The birds left the chimney only when one certain level of luminance was reached. Some environmental conditions influenced the departure from the daytime roost, too. So, we stated that, generally, the bird left the chimney few minutes later (when the temperature of the air was below 0 0 C, the sky coverage was below 50%, the sky was clear or covered with superior clouds, the wind blew, the Moon illuminated the landscape or a snow cover existed on soil) than in the other cases. In order to measure the amount of light, a light meter should have been used, but such an instrument was not available at that time. The direction of displacement from the daytime roost shows that its main places of feeding (buildings, stalls, gardens and orchards where it found various rodents and birds) were towards North, North-East, North-West and South. The presence of the female and the existence of possible place of breeding can be also taken into consideration. References Barco, A., Nedelcu, E., Județul Argeș. Editura Academiei. București. Benedek, A.M., Aspects regarding the small mammal communities (Ord. Insectivora and Ord. Rodentia) from the Sibiu Depression, based on Strix aluco and Asio otus pellets. Acta oecologica, Universitatea Lucian Blaga, Sibiu, XI, 1-2: König, C., Weick, F., Owls of the world. Second edition. A&C Black Publishers Ltd. London. Munteanu, D., Papadopol, A., Weber, P., Atlasul păsărilor clocitoare din România. Ediția a II a. Cluj Napoca. Petrescu, A., Contributions a l etude de la nourriture d hiver de trois especes d oiseaux de proie (Buteo lagopus, Accipiter nisus et Strix aluco) de Roumanie. Travaux du Museum d Histoire Naturelle "Grigore Antipa", XXXII:

8 Adrian Mestecăneanu & Florin Mestecăneanu Popescu, A., Savu, V., Date privind hrana păsărilor răpitoare de noapte, Athene noctua noctua Scop. și Strix aluco aluco L. Analele Universității București, XXX: Stellarium (online), accessed 10 April Available from: Savu, V., Contribuții la cunoașterea hranei speciilor de strigiforme, Athene noctua noctua Scop. și Strix aluco aluco L. în comuna Rușii-Munti și împrejurimi, județul Mureș. S.S.B. din R.S.R., Filiala Reghin, Stud. Comun. Reghin, II:

SMALL MAMMALS (INSECTIVORA AND RODENTIA) AS PREY OF LITTLE OWL (ATHENE NOCTUA SCOP.) IN THE SOUTH-WESTERN PART OF ROMANIA

SMALL MAMMALS (INSECTIVORA AND RODENTIA) AS PREY OF LITTLE OWL (ATHENE NOCTUA SCOP.) IN THE SOUTH-WESTERN PART OF ROMANIA IOANA NAE *, DUMITRU MURARIU ** The diet of the little owl, Athene noctua Scop.,