Ornis Hungarica 14: 1-13. 2004

Nest construction and roosting behaviour of a Crested Lark Galerida cristata population nesting on flat roofs in Hungary

Z. Orbán

Orbán, Z. 2004. Nest construction and roosting behaviour of a Crested Lark Galerida cristata population nesting on flat roofs in Hungary – Ornis Hung. 14: 1-13.

From the two basic types of flat roofs, one covered with shingle and the other with tar-boards, only the shingled roofs were selected for nesting by Crested Larks Galerida cristata. Breeding birds preferred the provided artificial breeding nestboxes to the natural, open nest sites. The nest sites were characteristically placed in locations that provided shelter and protection from the South or South-Western direction. As breeding coincides with the warmest months of the year this preference guarantees the highest breeding success, as these sites are the coolest. A roosting period precedes the incubation period, and overlaps with the primary phase of nest construction. Crested larks mostly spent the nights on those roofs where they later built their nests. Sites selected for spending the night were more scattered than nesting sites, and provid- ed protection mostly from the northern direction. As this period is the coolest part of the year, survival of the bird depends to a large extent on the ability of maintaining body temperature and conserving energy most efficiently. This goal might be best achieved through the avoid- ance of exposure to wind and keeping the feathers dry. Therefore birds prefer the most wind- protected locations on the roofs, which, at the same time, are also the driest.

Zoological and Botanical Garden of Jászberény, Fémnyomó u. 3., H-5100, Jászberény, Hungary. e-mail: [email protected]

1. Introduction Alaudidae, Turdidae (Cercomela, Oenanthe) and Fringillidae (Bucanethes) species breeding in these habitats con- Nest site selection of small ground-nesting struct their nests at locations protected by songbirds (Passeriformes) is basically stones or grass tussocks, or in under- influenced by the microhabitat. The vege- ground holes or rock cavities (Bannerman tation and micro-configuration of the ter- 1953, Cave & Macdonald 1955, rain might offer protection against the Mackworth-Praed & Grant 1960, 1962, wind, rain and overheating caused by 1970, 1973, Etchécopar & Hüe 1967, direct radiation from the sun (With & Maclean 1970, Orr 1970, Blotzheim & Webb 1993, Herranz et al. 1994). Bauer 1985, 1988, 1997, Paz 1987, Afik et Placement of nests is of outstanding al. 1991, Herranz et al. 1994). importance at those areas where the In colder or montane climates the weather is either very windy and cool, or micro-configuration of the terrain and veg- is characterised by sparse vegetation and etation provide protection mainly against excessive overheating during the day. In the wind (DuBois 1935, Verbeek 1967, 2 ORNIS HUNGARICA 14: 1 (2004)

Cannings & Threlfall 1981), and the posi- within a species cold and warm-tolerant tion of the nests, namely the direction to populations might evolve (Trost 1972, which the entrance faces, is determined by Walsberg 1993). But physiological adapta- the direction of prevailing wind during the tion can only reduce the deleterious effects incubation period. On open, sun-lit areas of the environment to a certain degree; the most problematic environmental factor thus birds have to also adjust their behav- is excessive overheating caused by direct iour to avoid further damage. Their daily sunlight, and hence nests are placed in a activity may change (Hickey 1993), just shadowed area. In this case the exposure of like the nest-constructing habits, day-time the nests depends on the geographical loca- resting (Ferns 1992) and night-roosting tion. In the Northern hemisphere in warm, behaviour (Trost 1972, Walsberg 1985, barren areas the entrance of the nests faces 1986, 1993). North, North-West or North-East Crested Larks inhabit the Northern (Ferguson-Lees 1962, Orr 1970, Blotzheim Hemisphere (Cramp 1988, Simms 1992), & Bauer 1985, Paz 1987, Afik et al. 1991, and in Central Europe it is the only lark With & Webb 1993, Herranz et al. 1994), species that does not migrate, either over- while South of the Equator, for example in wintering individually, or in small flocks the Kalahari Desert, the nest entrances face in the breeding areas. In Europe this South, South-East or East (Maclean 1970). species usually nests in areas with dense In the literature the direction of the nest plant cover, hence the nests, placed into entrances is often not mentioned, only the small depressions in the ground surface, shadowing effect of the vegetation and receive continuous shading (Pätzold micro topography is discussed (Bannerman 1986). Under the dry, semi-desert condi- 1953, Mackworth-Praed & Grant 1960, tions of the Near-East and North-Africa 1962, 1970, 1973, Alden et al. 1995). the nests are usually placed under grass Both the shape and the material from tussocks or in the shadow of a larger stone which the nest is constructed might influ- (Paz 1987). The entrance of the nests faces ence its ability to provide protection from to the North North-East (Simms 1992). the environment. The Mirafra (Alaudidae) Crested Larks spend the night on the species are characterised by nests above ground, in natural or self-made depres- which a roof is constructed from grass in sions, either alone or in pairs but often in order to provide shadow (Maclean 1970). flocks outside the breeding season (Cramp Desert Larks Ammomanes deserti 1988). In summer the locations selected (Alaudidae) build a protecting wall from for night roosting are usually open areas, stones around their nests (Etchécopar & while in late fall and winter roosting sites Hüe 1967, Mackworth-Praed & Grant are selected in vegetation covered, snow- 1970, Harrison 1980, Paz 1987), which is free areas (Cramp 1988). thought to have a thermo-regulatory Apart from the original natural habitats effect, and might aid self-incubation (Orr of this species (grassy or barren sites) birds 1970, Afik et al. 1991). often nest either inside, or in the close Birds can adapt to their environment vicinity of human settlements characterised by different climate by (Mackworth-Praed & Grant 1960, 1970, adjusting their metabolism, and hence Kovács 1984, Hollom et al. 1988). This Z. Orbán 3 fact is proved by the observation that this Hungarian city in Tolna county, where in is the only lark species of the region that an area of approximately one square kilo- uses paper and other man-made waste- metre around fifty blocks of flats are materials for the lining and insulation of located, all of them built with flat roofs. the nest (Etchécopar & Hüe 1967, Harrison Among these houses the ground is grass- 1980, Blotzheim & Bauer 1985, Pätzold covered and sparsely planted with trees 1986, Paz 1987). The phenomenon of and shrubs. using flat-roofs for nesting by this species In Dombóvár the average yearly sun-lit was reported from several European coun- hours amounts to approximately 2000 tries (Nagy 1926, Lindner 1928, Blotzheim hours, which is near the maximum in & Bauer 1985, Orbán 1999, 2000, Hungary, while the rainfall is only 600- Bankovics 1986, Peterson et al. 1986, 700 mm, which is near the country's aver- Pellinger & Frank 1987, Simms 1992), but age (Udvarhelyi 1968). The prevailing these mainly concern grass-covered flat wind direction is North-Westerly roofs (Blotzheim & Bauer 1985). Cramp (Udvarhelyi 1968). (1988) also quotes other authors who detected night roosts on flat roofs. 2.2. Flat roofs The flat roofs of concrete blocks of flats are usually elevated 15-20 meters During the fifteen years of this study 19 above the surrounding habitat, and they different roofs were checked. The average represent isolated, comparatively small number of roofs checked in a given year habitat islands characterised by special was 10.6±3.5 (SD) (range: 1-17, n=15 environmental circumstances. The physi- years). Two types of flat roofs exist in the cal parameters of these habitat islands are study area: one is felted, while the other is very different from those found at ground covered with yellow shingle, under which level. As this species does not migrate, the there is a layer of black bitumen. These various behavioural elements can be read- flat roofs are not totally empty construc- ily observed and studied throughout the tions, television antennas, air funnels and year in the almost laboratory-like, easily construction debris can often be found on manipulated environment of the flat roofs. them. The surface of the roofs is levelled My main aim was to explore and in such a way that water runs down from describe the microhabitat characteristics the edges toward the centre of the roofs, of flat roofs, and analyse their effects on where drain pipes lead the rainfall down to the incubating and roosting behaviour of the gutters. All the flat roofs are emar- Crested Larks. ginated with a cornice or ledge of approx- imately 20-80 centimetres height. These ledges are covered either by tar boards or 2. Methods corrugated iron. On flat roofs covered with tar boards the wind accumulates sand 2.1. Study area in the corners formed by the ledges, and after 10-20 years the accumulation might _ This study was carried out from 1984 until be several centimetres thick (x=11.3 cm 1998 in the centre of Dombóvár, a length by 9.0 cm width by 2.6 cm depth, 4 ORNIS HUNGARICA 14: 1 (2004) n=8). On roofs covered by shingle accu- ed any sign suggesting the presence of mulated sand was not detected. Among the crested larks on a roof I tried to check it studied roofs 11 were shingle covered and more often, weekly or often daily or in 8 were felted. The area of the roofs was some cases several times a day. If it was quite variable, the average being possible I removed the nests from the 681.6±287.1 m2 (SD) (range: 250-1000 m2, roofs and also from the nestboxes after the n=19). The smaller roofs are constructed incubation was over. as a single, continuous unit, while the larger ones are constructed as a facet of 2.5. Temperature, humidity and rain- sub-units, and these are emarginated with fall measurements individual ledges. The average number of roof sub-units is 1.7±1.2 (SD)(range: 1-4, The air temperature was measured in the n=19). four ledge-corners and in the open centre of a shingle-covered roof at a height of 3 2.3. Nestboxes cm. Air temperature was measured both over the yellow shingle and a larger black During the study soil-filled nestboxes tar surface at the height of 3 centimetres. were placed on shingle covered flat roofs A thermometer at the height of 1.5 metres for crested larks (Orbán 2000). On six in the shadow was also operated. roofs a single nestbox was placed, while Temperature measurements were carried on a roof constructed of three sub-units a out in the May of 1990; the data was col- single nestbox was placed into every unit. lected every hour. The nestboxes were placed either in the Relative humidity was measured corners or in the middle of the roofs. hourly in one shadowed and one sun-lit Between 1984-1994 the average number ledge corner parallel with each other with of nestboxes per year was 6.1±2.5 (SD) an analogue humidity-meter. (range: 1-9, n=11). As a consequence of The rainfall was measured in 250 ml the reconstruction of the roofs all the nest- laboratory graduate measuring glasses at boxes were destroyed, and hence in the the four ledge corners and in the open cen- last four years of the study (1995-1998) tre of the same roof where humidity mon- there were no nestboxes operated on the itoring was also carried out. Rainfall data roofs. was collected over four years (1987-1990) in the nesting period from March until 2.4. Flat roof checkings August. For the sake of more precise mea- surements the often minuscule amount, The roofs were checked all year around, rain was poured into a test tube, and the both during the day and night, and I tried height of the water was measured with a to check all the studied roofs on every ruler truncated at zero (Svensson 1995). occasion. During the breeding season Measurements were only considered valid (March-August) and outside the breeding when they were carried out immediately season (September-March) at least one after rain, and hence evaporation did not check was performed a month. If I detect- alter the result considerably. Z. Orbán 5

40 were placed on shingle-covered roofs, and

On the surface of the flat roofs 60.6% of these nests were placed in nest- In the nestboxes boxes, the remaining 39.4% being con- structed on the surface of the roofs them- 16 15 selves (Fig. 1).

9 In the nestboxes the nest cavities were Number of Nests 11 1 (diameter×depth) smaller than in the open NW _ _ 1 SW ones (xnestbox=68.2×52.3 mm, n=3; xopen 1 Other places NE roof=77.5×76.5 mm, n=2). The open nests SE Position of Nests were more than eight times heavier than _ Fig. 1. The spatial distribution of nests accord- the ones constructed in nestboxes (x _open ing to their position on the surface of the flat =309.1±258.4 g [SD], n=6; x roofs (n=37) and within the nestboxes (n=57). roof nest- =37.1±13.5 g [SD], n=6), and this differ- Ledge corners and nestbox corners are indicat- box ed as SW, SE, NE, NW corners. The open posi- ence was significant (two-samples t-test, tion category indicates nests built in central p=0.05). This large difference is caused by positions on the roofs or within the nestboxes, the fact that in the open nest the crested these could be either completely open or pro- larks accumulate pieces of concrete and tected from one direction if they are built adja- other stones as nest material (Orbán cent to some objects. 1999), and in the open roof nests much more stone is incorporated than in the one 3. Results in the nestboxes. In the case of four differ- ent nests construction took one, four, six 3.1. Nest constructing behaviour and nine days, respectively. Although nest initiations were first detected in February, During the study 94 nests were monitored. and the earliest completed nests were Only a single attempt (1.1%) of nest-con- found in March, nesting, egg laying and struction was detected on a felted roof, in incubation mainly started in April, and a South-West ledge corner. This nest was continued into August (Fig. 2). not completed, and no incubation was per- Of the open nests, 75.7% were placed formed. The remaining 93 nests (98.9%) in ledge corners, 24.3% were placed into

40 central areas either in the shadow of some 37 Breeding objects or openly (Fig. 1). Inside the nest- 35 Night roosting boxes 73.7% of nests were placed in cor- 30 ners, 26.3% were in the centre more or 25 less covered by plant material or in a com- 20 17 pletely open position (Fig. 1). Pooling the 15 13 nests, the majority (94.7%; n = 89) were 10 10 9 9

Number of Observations 7 protected from one side: 69 (73.4%) nests 5 5 3 3 were protected from South-West, 14 1 1 1 0 (14.9%) from South-East; 2 (2.1%) from JFMÁMJJASzOND Month North-West, 1 (1%) from North-East, and Fig. 2. Temporal distribution of nesting and finally 3 nests (3.2%) were covered from night roosting on the flat roofs. above completely. Altogether only 5 6 ORNIS HUNGARICA 14: 1 (2004)

On felted roofs although only from a single roof, I also 17 On shingled roofs found traces indicating roosting. 14 13 The ratio of droppings only roost type was smaller on tar-board covered roofs 10 (7.7%, n=13 roosts) than on shingle-cov- 7 ered roofs (64.3%, n=70 roosting sites). 4 4 4 4 During the year, on the shingle-covered

Number of Roost Sites 1 4 roofs there is a marked transition from the 1 NW W N depression type (January 100%, February SW In open positions NE S 100%, March 2.4%, April 0%) towards the SE Position of Roost Sites droppings only type roost (January 0%, Fig. 3. The distribution of roost sites on the February 0%, March 97.6%, April 100%). roofs. For legend see Fig. 1. On the more protected parts of the roofs both types of roosts occurred, while on the (5.3%) nests were constructed in a com- more exposed parts only the depression pletely open position. type of roost was found. Sometimes (in July and in September) the depressions 3.2. Night-roosting were located very near each other, the maximum being eight roosting places Two different kinds of traces indicating within a square meter (in July). night roosting were separated: droppings The freshness of droppings could be and small roosting depressions. In the for- estimated by their colour. Under wet, mer case the accumulated faecal matter humid weather conditions the older drop- indicated roosting, while in the latter case pings become brownish, whilst the fresh shallow depressions were prepared by the ones remain white for one or two days. birds, in which they spent the night. The Based on the amount and colour of the dimensions of these depressions were droppings it was possible to estimate _ x=11.2×8.5×1.9 cm (length by width by whether the roosting site was used for a depth) on both types of roofs. long or short period of time. On the shin- During the study period on the roofs 83 gle-covered roofs, taking into account signs of night roosting were found. From both roost types the area covered with these 84.3% were on shingle-covered, and droppings was on average 16.3 cm2 (n=5 15.7% on felted roofs (Fig. 3). On the roost sites), and its thickness was several shingle-covered roofs between 1985-1998 centimetres. They were usually composed every year, while on the felted roofs only of both older brownish and fresh white in a single year (1991) were signs of night- droppings. Even where thickness of the roosting detected. From the data collected accumulated faeces was not so thick more for over 14 years on the shingle-covered than ten droppings were usually found at a roofs, the night roost usually lasted from single site. Based on these findings we can January until April (Fig. 2), as only in state that the majority of roosting sites these months were traces of roosting were used over several nights. detected every year from more than one Based on the pooled samples from both roof. In July 1992 and September 1998, tar-board covered and shingle-covered Z. Orbán 7

55 of the roof get uneven amount of irradia- NE 50 tion from the sun. Therefore the directly 45 sun-lit areas warm up more quickly (Fig.

40 SE 4). The temperature differences disappear 35 NW as direct sunlight ceases to hit the roof, 30 usually in the evening hours when all the Temperature (C°) Open 25 SW roof area is in shadow, and temperature 20 equalisation takes place very quickly (Fig. 15 4, see the 20.00 h temperature data). The 4689101112131415161718192021 Time (h) differentiation in temperatures starts only Fig. 4. The daily dynamics of temperature after sunrise, when sunlight begins to fall change in the ledge corners and in open posi- directly on the flat roofs (Fig. 4, see the tions of a shingled roof. Data was recorded 8.00 h temperature data). All the ledge during the daylight hours in completely cloud- less weather (16.05.1990.). corners receive direct sunlight, but the greatest exposure to the sun’s rays is roofs 84.3% (n=70) of the night roosts detected in the Northern corners (Fig. 4). were located at the protected parts of the The south-western corner is exposed only roofs, from which 48.2% (n=40) were for a few minutes in the early morning, sheltered from North whereas 31.3% and the south-eastern corner is irradiated (n=26) from the South (Fig. 3). On the sin- in the afternoon (Fig. 4). Although the gle felted roof the southern protection was open surfaces are sunlit, they become less more frequent (61.5%; n=9), while on the hot, than the ledge corners of similar shingle-covered roofs the northern protec- exposure (Fig. 4, for example compare the tion was more wide-spread (50%, n=35). open and NE, NW locations between 12- If we compare the orientation of the 14 hours), because the vertical walls of the nest and roost sites on the shingle-covered ledge function as additional heat trapping roofs, the nests (open site and within nest- surfaces, and they radiate the warmth back box nests combined) are characterised by into the corners. In May (17th May, 1990. protection from the South (88.3%, n=83), 12 hour) the highest temperature, 53C°, while the night roosts are mostly protected was measured in the North-western ledge from the North (50%, n=35). corner. The air temperature at 1.5 metres Birds spend the night in depressions was equal with the temperature measured prepared in the soil of the nestboxes, in the South-western corner. There was no placed on shingle-covered roofs, or in the difference between the temperatures mea- nests remaining from the former nesting sured on the shingle-covered and felted _ _ season only in January and February. roofs (xshingle-covered roofs=32.8C°, xfelted

roofs=32.8C°). 3.3. Temperature, humidity, precipita- The humidity values of the directly tion irradiated open surfaces were lower, than that of those measured in the shadowed As a consequence of the different shading South-Western ledge-corners. The humidi- provided by the ledges and other objects ty changed in indirect proportion to the constructed on the roofs the different areas rise and fall of temperature (Fig. 5A, B). 8 ORNIS HUNGARICA 14: 1 (2004)

70 A 70 65 65 B 60 60 SW 55 55 Ope 50 (C°) 50 (%) 45 45 40 40 35 35 Humidity Temperature 30 30 Open 25 25 SW 20 20 15 15 7 8 9 10 11 12 13 14 15 16 17 18 19 20 7 8 9 1011121314151617181920 Time (h) Time (h) Fig. 5. The daily dynamics of temperature (A) and humidity (B) change on the same roof as in Fig. 4. measured in parallel with each other in open, sunlit position and in the south-western shadowed ledge corners (19.05.1990.). There is no significant difference be constructed, and as the construction among the average amount of precipita- requires less energy, it is advantageous for tion measured in the five rainfall monitor- the birds to prepare their nests in these. ing locations (ANOVA, F4,35=1.38, This might explain why the majority of p>0.05). nests are constructed in the nestboxes Although there were no instrumental (Fig. 1). wind pressure measurements carried out The sides of the nest-cups, prepared in on the roofs, it is certain that there are the soil are strengthened by the soil sur- strong wind pressure peaks on them. This rounding the nest itself. However, nests is shown by the fact that the precipitation built on flat roofs can only be strength- measuring tubes were often turned over by ened by the objects against which they are the wind, and their upright position had to constructed, and therefore all the nests on be secured by stones. the roofs are prepared adjacent to objects, which can reinforce them, most often in 4. Discussion the corners of the ledges. All other Hungarian data also stresses the impor- tance of ledge corners (Bankovics 1986, 4.1. Nest construction Pellinger & Frank 1987). On one of the felted roofs, the wind Under natural conditions Crested Larks accumulated several centimetres of sand nest either in shallow natural depressions in the ledge corners, and the Crested larks in the soil, or in depressions they prepare prepared night-roost sites in this material. themselves. As there are no such natural In the accumulated sand the birds could nest sites on flat roofs, and the birds can have prepared their nests more easily, not scrape a depression into the hard sur- however, none of the nests made on the face, they have to prepare the nest depres- felted roofs were located in these sandy sion in the nesting material they accumu- corners. Bankovics (1986), and Pellinger late on the roof. Because of the extra nest- & Frank (1987) found nests only on the ing material used for their construction shingle-covered roofs. This finding is pos- these nests are considerably heavier, and sibly explained by the fact that nestlings their preparation requires more energy. In leave the nests before they become fully the nestboxes smaller and lighter nests can capable of flying (Ferguson-Lees 1962, Z. Orbán 9

Reade & Hosking 1974, Harrison 1980, roofs constitute an extreme warm climate Blotzheim & Bauer 1985, Paz 1987, due to the lack of vegetation. During more Cramp 1988, Simms 1992). Nestlings than half of the nesting period in the ledge become capable of flying when they are corners the temperature considerably 15-20 days old (Reade & Hosking 1974, exceeds 43-45C° established as the critical Harrison 1980, Blotzheim & Bauer 1985, values for small passerine birds (Trost Paz 1987, Cramp 1988.) However, based 1972, Walsberg 1993). Only a single nest on the observations of the previous was constructed in such a North-West authors and myself the nestlings venture ledge corner, but under a plastic sheet that from the nest at 8-11 days of age, when provided continuous shading. The open, they are capable of running and jumping. directly sun-lit areas because of the lack of Hence they can not overcome the obsta- neighbouring heat reflecting surfaces cles created by the ledges of the roof. warm up to a lesser extent than the Until they become fully capable of flight Northern ledge corners. Therefore for nest they must spend 7-10 days on the roofs. sites even the open positions are prefer- Nestlings rely only on their camouflage able to Northern ledges. The Southern against birds of prey detected in the study ledge-corners are also receiving direct area (Accipiter nisus, Accipiter gentilis, sunlight, but as the South-Eastern corner Falco subbuteo, Asio otus, Tyto alba, is sun-lit only in the late afternoon hours, Lanius collurio, Corvus frugilegus, they do not warm up as much as the North- Corvus monedula). The post-juvenile Western corners, which are hit by the sun- feathers with their lighter spots and light for about the same length of time but brownish ground colour match perfectly in the warmest hours. The South-Western the pattern and colour of the shingle-cov- corners are sun-lit only for a short period ered roofs, but on the black tar boards this of time the early morning hours. This the appearance would be useless. The assump- most advantageous for breeding, because tion could be made that mortality during after the chill of the night this corner is the nestling phase would be considerably warmed up quickly, and than becomes higher on the felted roofs due to the lack shadowed for the rest of the day. South- of effective camouflage. Western corners are also more advanta- geous from the point of view of relative 4.2. Orientation of the nests humidity, than the directly sun-lited parts of the roofs. Natural water-loss of eggs In the study area July and August are the during incubation is 9-18%, and the actual warmest months. Maximum temperature value is strongly influenced by the humid- measured in May (53C°) was higher than ity of the immediate environment of the those measured by Trost (1972) in the nests (Walsberg 1985). In the South- Mojave Desert (47C°), and Orr (1970) in Western corners, characterised by the low- the Negev (43.8C°). Although I measured est and most stable temperature, higher considerably higher maximum tempera- humidity creates more preferable condi- ture in the Libyan Desert in direct sunlight tions for nesting than the open, directly (57.4C°; Egypt, Marsa Matruh, sun-lit roof sectors. 15.04.2000.), there is no doubt that the flat On the studied flat roofs nests were 10 ORNIS HUNGARICA 14: 1 (2004) most often (73.4%) constructed in loca- period or in the cool nights. This negative tions protected from South-Western direc- effect is further stressed when the feathers tion. This orientation is the most prefer- of the birds are wet. Consequently for able as regards to temperature characteris- roosting birds it is essential to find dry and tics, but from the point of view of rain wind-protected sites. Walsberg (1986) exposure almost the worst, only the com- measured 18-30% lower wind velocity fig- pletely open roof sectors receive more ures on the roost sites of Phainopepla rain. While overheating caused by sunlight nitens (Passeriformes) compared to their is a daily phenomenon on the flat roofs in immediate surroundings. Roosting birds the nesting period rain is experienced only prefer denser foliage or nests cavities to weekly or monthly. Overheating at some sites that provide less protection against parts of the roofs exceeds the tolerable wind (Walsberg 1985). Most of the roost physiological maximum daily, while the sites (91.7%) located on the studied flat amount of rain is usually not extreme. roofs were at wind-protected sectors of the Both the daily frequency and the often roof. Besides lowest wind pressure these extreme values of temperature constitute corners are also providing the best protec- stronger environmental selective pressure tion against rain driven by the prevailing for nesting than the infrequent and rarely wind. This helps keeping the feathers dry excessive rainfall, which can not accumu- and hence maintain their insulation capa- late on the roofs. Through the selection of bility. Based on my measurements actual South-Western corners birds opt for min- exposure to rain is influenced not only by imising the risk arising from the intolera- the protection, but also by the actual direc- ble overheating, and are choose to with- tion of wind that might change from one stand the hardships created by precipita- rainy period to the other. The actual roost- tion. ing site is usually selected according the wind direction on the given day, and this 4.3. Roosting behaviour might explain the scattered pattern of roost site orientation/exposure experi- In our study area the first part of the peri- enced on the roofs. od when Crested Larks roost on the roofs In the lack of properly protecting veg- (January-April) coincide with the coldest etation some species spend the night in months of the year in Hungary. In January- small depressions scraped into the ground February -10 – -15C° minimum tempera- (Trost 1972, Cramp 1988), and Crested tures are quite common, and temperatures Larks also use underground cavities on between -20 – -34C° might also occur flat roofs (Cramp 1988). According to occasionally. In March-April nights are Trost (1972) Horned Larks Eremophila usually milder, but temperatures below alpestris in laboratory experiments always zero still occur. prepare roosting depressions under 10C°, For small passerines the fall in body while above 25C° they never prepare such temperature caused by the wind, humidity roosting cavities. On the studied flat roofs and low temperatures pose the greatest in the coldest months, January-February, hazards during night. Windchill is espe- the roosts were small depressions scraped cially devastating in the cold of the winter sometimes inside the nestboxes or more Z. Orbán 11 often in the shingle, but all of them were sions can be prepared, and this might com- located in the protection of ledges or the pensate for the less favourable exposure. sides of the nest boxes. Roosting in nest- According to Trost (1972) Horned boxes and nests were observed only in this Larks use roosting cavities alone. Based (January-February) period. In March- on the size of roosting depressions Crested April a marked warming up starts, and Larks spend the night alone, too. But at the thereafter birds do not scrape depressions non-depression type roost I observed sev- for roosting, the roost sites are only eral times to individuals cuddled together marked by their droppings. during the night. The roosting depressions The roosting birds even in the warm are also often clumped together in large summer period preferred the protected numbers (Trost 1972, Cramp 1988). sectors of roofs. All of the roosting Sometimes on the roofs there are several nestlings choose the corners, predomi- roost depressions scraped near each-other, nantly the most wind-protected Northern the maximum was 8 depressions in 1m2 in ones. If the roosting site was selected at an July. open location always a depression was Trost (1972) reports that a new depres- created, where birds get more protection. sion is prepared in the soft soil every day, At most (76.9%) of the roost sites located while in harder soil the same cavity is used in open parts there were no droppings, and for several days. This is further evidenced it suggests that these open sites were by the fact that only 2-3 droppings were either not used at all, or only for a single found in the depressions prepared in soft night. The night-roosts, found on the open soil, while the depressions prepared in part of the roofs in July 1992, also lacked hard soil contained 10-15 droppings. On any droppings, and were all depression the roofs both the colour (white and brown types. This suggests that even under mixed) and the amount of droppings sug- favourable conditions birds still try to gest that the roost sites are used for sever- maximise the protection offered by their al days. If we consider that the depressions roosting site. are prepared during the day, and hence The location of roosting sites was dif- reduce the time available for foraging ferent on the shingled and felted roofs. On (Trost 1972, Cramp 1988), prolonged use the shingled roofs Northern protection is of the depressions can help save time and dominant, while on the single felted roof energy in the coldest period. Multiple use Southern protection was detected more was also detected in the case of non- often (61.6%). On the felted roof wind has depression type of roost sites. accumulated heaps of debris. The thick- Most of the roosting was performed on ness of the debris depends on the age of shingle covered roofs. A possible explana- the roofs and wind direction. Under the tion might be that roosting precedes and prevailing North-Western wind more overlaps with the beginning of the nesting debris is accumulated in the North- period, and roosting site selection might Eastern, South-Western and South-Eastern be a prelude to establishing the breeding corners than in the protected North- territories. Hence the felted roofs are not Western ledge-corner. In the thicker debris used for roosting because later on nesting deeper, more protective roosting depres- is not performed on them. 12 ORNIS HUNGARICA 14: 1 (2004)

Acknowledgements. I would like to express my Alden, P. C., Estes, R. D., Schlitter, D. & McBride, gratitude to all those persons who helped me to B. 1995. National Audubon Society Field Guide carry out these investigations. Róbert Tálos to African Wildlife. – Alfred A. Knopf, New gave help in the deploying of nest-crates, York. Bannerman, D. A. 1953. The Birds of West and György Miklay were instrumental in the com- Equatorial Africa. – Oliver and Boyd, puter data processing. Dr. Tibor Csörgő and Dr. Edinburgh. Erzsébet Pásztor checked the manuscripts, and Bankovics, A. 1986. Búbos pacsirta Galerida crista- also gave advice on the statistical analyses. ta fészkelése háztetőn. – Madártani Tájékoztató, január- március: 69-70. Glutz von Blotzheim, U. N. & Bauer, K. M. 1985. Összefoglalás Handbuch der Vögel Mitteleuropas. Band 10/I. – AULA-Verlag, Wiesbaden. Glutz von Blotzheim, U. N. & Bauer, K. M. 1988. Fészeképítés és éjszakázó viselkedés egy Handbuch ger Vögel Mitteleuropas. Band 11/I. – lapos tetőkön élő búbospacsirta AULA-Verlag, Wiesbaden. Glutz von Blotzheim, U. N. & Bauer, K. M. 1997. Galerida cristata populációban Handbuch der Vögel Mitteleuropas. Band 14/II. A lapos tetők két típusa, a gyöngykavicsos és a – AULA-Verlag, Wiesbaden. kátrányos közül a búbospacsirták csak a Cannings, R. J. & Threlfall, W. 1981. Horned Lark breeding biology at Cape St. Mary_s, gyöngykavicsos tetőkön költöttek. A költő ma- Newfoundland. – Wilson Bull. 93: 519-530. darak a tetőkre kihelyezett költőládákat prefe- Cave, C. F. O. & Macdonald, J. D. 1955. Birds of the rálták a tetőfelszíni fészkelő helyekkel szem- Sudan. – Oliver and Boyd, Edinburgh. ben. A fészkek elhelyezkedésére a déli és dél- Cramp, S. (eds). 1988. The Birds of Western nyugati védettség volt a jellemző. Mivel a köl- Palearctic. Vol. 5. – Oxford University Press, tési időszak az év legmelegebb hónapjaira esik, Oxford. e fészekhelyek hőmérséklete a legalacsonyabb, DuBois, A. D. 1935. Nest of Horned Larks and legkedvezőbb a költési siker szempontjából. Longspurs on a Montana praire. – Condor 37: 56-72. Az éjszakázási időszak a költési időszakot köz- Etchécopar, R. D. & Hüe, F. 1967. The Birds of vetlenül megelőző és annak korai szakaszára North Africa from the Canary Islands to the Red tehető. A pacsirták elsősorban azokon a tető- Sea. – Oliver and Boyd, Edinburgh and London. kön éjszakáztak, ahol később költöttek is. Az Ferguson-Lees, I. J. 1962. Studies of less familiar éjszakázóhelyek szórtabban helyezkedtek el, birds, 116. Crested Lark. – Brit. Birds 55: 37-42. mint a fészkek, s azoktól eltérően elsősorban Ferns, P. N. 1992. Thermoregulatory behavior of északi irányból voltak védettek. Mivel az éj- Rock Doves roosting in the Negev Desert. – J. szakázási időszak az év leghidegebb hónapjai- Field Ornithol. 63: 57-65. Harrison, C. 1980. A Field Guide to the Nest, Eggs ra esik, az éjszakázó madár túlélése a testhő- and Nestlings of British and European Birds. – mérséklet energiatakarékos fenntartásának si- Collins, London. kerétől függ. Ez a szélterhelés csökkentésével, Herranz, J., Manrique, J., Yanes, M. & Suarez, F. és a tollazat szárazon tartásával érhető el. Ezért 1994. The breeding biology of Dupont's Lark az éjszakázó madarak a legszélvédettebb he- Chersophilus duponti, in Europe. – Avocetta 18: lyeket részesítik előnyben a tetőkön, melyek 141-146. egyben a legszárazabbak is. Hickey, M. B. C. 1993. Thermoregulation in free- ranging Whip-poor-wills. - Condor 95: 744-747. Hollom, P. A. D., Porter, R. F., Christensen, S. & Willis, I. 1988. Birds of the Middle East and References North Africa. – T & A D Poyser Ltd., Calton, England. Kovács, G. 1984. Búbospacsirta. Pp. 137-138. In: Afik, D., Ward, D. & Shkedy, Y. 1991. A test of the Haraszthy, L. (eds). Magyarország fészkelő self-incubation hypothesis for desert bird that madarai – Natura, Budapest. build a rampart of stones in front of their nests. – Lindner, K. 1928. A búbospacsirta költése J. Therm. Biol. 16: 255-260. háztetőkön. - Aquila 32-33: 398. Z. Orbán 13

Mackworth-Praed, C. W. & Grant, C. H. B. 1960. Pellinger, A. & Frank, T. 1987. Megfigyelések a Birds of Eastern and North Eastern Africa. búbos pacsirták Galerida cristata urbanizá- African Handbook of Birds, Series I., Volume 2. ciójáról. – Madártani Tájékoztató 3-4: 29-30. – Longmans. Peterson, R. T., Mountfort, G. & Hollom, P. A. D. Mackworth-Praed, C. W. & Grant, C. H. B. 1962. 1986. Európa madarai. 4. kiadás. – Gondolat, Birds of the Southern Third of Africa. African Budapest. Handbook of Birds, Series II., Volume I. – Reade, W. & Hosking, E. 1974. Vögel in der Longmans. Brutzeit. – Verlag Eugen Ulmer Stuttgart. Mackworth-Praed, C. W. & Grant, C. H. B. 1970. Simms, E. 1992. British Larks, Pipits and Wagtails. – Birds of West Central and Western Africa. Harper and Collins Publishers. African Handbook of Birds, Series III., Volume Svensson, L. 1995. Útmutató az európai I. – Longmans. énekesmadarak határozásához. – Magyar Mackworth-Praed, C. W. & Grant, C. H. B. 1973. Madártani és Természetvédelmi Egyesület, Birds of West Central and Western Africa. Budapest. African Handbook of Birds, Series III., Volume Trost, C. H. 1972. Adaptations of Horned Larks II. – Longmans. Eremophila alpestris to hot environments. – Auk Maclean, G. L. 1970. The biology of the Larks 89: 506-527. Alaudidae of the Kalahari Sandveld. – Zoologica Udvarhelyi, K. 1968. Magyarország természeti és Africana 5 (1): 7-39. gazdasági földrajza. - Tankönyvkiadó, Budapest. Nagy, J. 1926. Galerida fészkelése a háztetőn. – Verbeek, N. A. M. 1967. Breeding Biology and ecol- Aquila 32-33: 263. ogy of the Horned Lark in alpine tundra. – Orbán, Z. 1999. Desert type nest building behaviour Wilson Bull. 79: 208-218. of a Crested Lark Galerida cristata population Walsberg, G. E. 1985. Physiological consequences of nesting on flat roofs in Hungary. – Túzok 4(3): microhabitat selection. Pp. 389-413. In Cody, M. 63-72. (In Hungarian, with English summary). L. (eds). 1985. Habitat selection in birds. – Orbán, Z. 2000. Application of nest boxes to facili- Academic Press, Orlando, FL. tate the nesting of Crested Larks Galerida crista- Walsberg, G. E. 1986. Thermal consequences of ta on flat building roofs. – Túzok 5 (1-2): 102- roost-site selection: the relative importance of 108. (In Hungarian, with English summary). three modes of heat conservation. – Auk 103: 1- Orr, Y. 1970. Temperature measurements at the nest 7. of the Desert Lark Ammomanes deserti deserti. – Walsberg, G. E. 1993. Thermal consequences of diur- Condor 72: 476-478. nal microhabitat selection in a small bird. – Paz, U. 1987. The Birds of Israel. – The Stephen Ornis Scandinavica 24: 174-182. Green Press, Lexington, Massachusetts. With, K. A. & Webb, D. R. 1993. Microclimate of Pätzold, R. 1986. Heidelerche und Haubenlerche. ground nest: the relative importance of radiative Die neue Brehm-Bücherei 440. – A. Ziemsen cover and wind breaks for three grassland Verlag, Wittenberg Lutherstadt. species. – Condor 95: 401-413.