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ISSN 0869-4362
Русский орнитологический журнал 2001, Экспресс-выпуск 142: 355-369
Studying the behaviour of birds
during the solar eclipse on August 11, 1999
Dimitar Nankinov*, Svetla Dalakchieva, Boris Nikolov, Petar Shurulinkov, Konstantin Popov, Svetlan Kirilov, Katerina Zareva, Borislav Borisov, Georgi Stojanov, Nikolai Nankinov, Nikolai Minchev, Dinjo Kjichukov, Ivailo Nikolov, Radoslav Stanchev, Evgeni Ganchev
* Institute of Zoology, Bulgarian Academy of Sciences, boul. Tzar Osvoboditel, 1, P.O. Box 445, 1000, Sofia, Bulgaria
Received 11 March 2001
The solar eclipse on August 11, 1999 covered the whole territory of Bulgaria. It was total to northeast from the line connecting Ruse and Varna, and partial in the rest of the country. The beginning of the partial eclipse was at 12 -1246 in the different regions. The moon shaded the sun completely between 1401 and 1412 and the end of the partial eclipse was at 1524-1534. The solar eclipse is an extreme situation of fast reduction and after that fast restoration of the power of the solar impact on the Earth. Specific changes in the magnetosphere, ionosphere and atmosphere appear during the solar eclipse, when the flow of the solar radiation and corpuscular flex decrease sharply. The air temperature near the surface drops and the earth magnetic field varies strongly (Dermendjiev et al. 1999). As a natural phenomenon the solar eclipse influences the animals on the Earth. Unfortunately the matter is almost unstudied not only in Bulgaria, but in the whole world. There are only notes of common character, mainly in press and popular publications (some of them distorted and exaggerated) about the reactions of the domestic and wild birds during previous eclipses. Our study is a realisation of the National Programme of Bulgarian Academy of Science for studies and observations during the solar eclipse on August 11, 1999.
Materials and methods
The Bulgarian Ornithological Centre organised on a large scale observations of birds behaviour during the solar eclipse. They were performed with united methods in 16 points in Bulgaria: 6 in the zone of the total solar eclipse and 10 in the zone of the partial solar eclipse (Fig. 1, Table 1). More than 30 professional and amateur ornithologists, collaborators of the Bulgarian Ornithological Centre participated in these studies. The answers of the following main questions were looking for: 1) can the birds predict the solar eclipse? 2) how the birds apprehend and react to this phenomenon? 3) are there any residual reactions in the birds behaviour as a consequence of the past solar eclipse. A special instruction was prepared for this purpose. The observations were performed simultaneously by all participating ornithologists. They began at Ю00 a.m., e.g. two and a half hours before the beginning of the solar eclipse and finished at 1800 — two and a half hours after the end of the eclipse. We used field binoculars and scopes. Also a fullday studies from the waking of birds till their falling asleep (from 600 a.m. till 2130) were performed on August 10th, 11th and 12th in the garden of the Royal Palace in
the centre of Sofia. The feeding activity of 4 species: European Nuthatch, House Sparrow, Great and Blue Tits, was studied on a permanent feeder (Fig. 2). We recorded every change in birds behaviour. So a total of 166.5 hours of field observations of birds behaviour during the solar eclipse were performed in different points in the country. We observed 14 254 specimens of 133 species, which is 32% of the composition of Bulgarian avifauna.
Species and numerical composition of the birds observed during the solar eclipse on August 11,1999
Species Observant points Total
1 2 3 4 5 6 I 7 8 9 10 11 12 13 14 15 16
Podiceps cristatus 15 15 Phalacrocorax
carbo 3 3 6
Ph. aristotelis 10 10
Ph.pygmeus 1 60 10 25 15 6 117 Pelecanus
onocrotalus 200 1800 2000
Ardeola ralloides 1 4 5
Egretta garzetta 1 10 4 3 9 27
Egretta alba 1 1
Ardea cinerea 10 3 18 31
A. purpurea 6 6
Ciconia nigra 4 4
C. ciconia 8 1000 3 120 200 1444 714 3489
Plegadis falcinellus 1 23 24
Platalea leucorodia 16 16
Cygnus olor 2 2
Anas strepera 1 1
A. platyrhynchos 50 70 210 330
A. querquedula 20 8 28
Aythya nyroca 3 3
Pernis apivorus 2 2 Neophron
percnopterus 2 2
Circaetus gallicus 111 2 5 Circus
aeruginosus 7 5 2 2 16
C. pygargus 1 1
Accipiter gentilis 11 1 3
Buteobuteo 2 2 5 3 1 2 15
Buteo rufinus 6 6
Falco tinnunculus 1 1 5 2 2 11
Falco eleonorae 1 1
Coturnix coturnix 2 2 1 5 Phasianus
colchicus 1 1
Rallus aquaticus 1 1
Gallínula chloropus 13 15
Fúlica atra 15 15
Species Observant points Total
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Haemantopus
ostralegus 3 3 1 7 Himantopus
himantopus 23 23 Burhinus
oedicnemus 3 3
Glareola pratíncola 3 3
Charadrius dubius 4 8 4 2 18
Ch. alexandrinus 3 8 1 12 Pluvialis
squatarola 5 5
Vanellus vanellus 8 5 6 19
Calidris minuta 19 10 29
Calidris alba 1 1 Philomachus
pugnax 40 5 45 Numenius
phaeopus 1 1
Numenius arquata 2 2
Tringa totanus 3 3 20 53 79
T. erythropus 30 30
T. stagnatilis 1 1
T. glareola 45 10 55
Actitis hypoleucos 5 4 3 1 13
Larus minutus 10 10
L. melanocephalus 40 40 50 130
L. ridibundus 1 50 50 80 15 112 308
L. geneii 5 5
L. cachinans 1 50 50 140 140 30 405 1 817 Gelochelidon
nilotica 1 1 Sterna
sandvicensis 20 20
S. hirundo 2 10 30 42
Chlidonias hybrida 6 6
Ch. nigra 40 60 100 Columba livia
f .domestica 200 11 211
Streptopelia turtur 40 30 70
S. decaocto 2 2 2 2 8
Cuculus canorus 1 1
Otus scops 1 1
Athene noctua 1 1 2
Asio otus 1 1
Apusapus 4 6 15 25
Apusmelba 50 80 130
Alcedo atthis 1 5 3 9
Merops apiaster 5 15 65 100 185
Species Observant points Total
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Upupa epops 5 2 7
Picus viridis 2 2
Picoides major 4 4
P. syriacus 1 2 1 4
P. minor 1 1
Galerida cristata 10 10 4 24
Alauda arvensis 20 3 23
Riparia riparia 150 200 6 50 406
Hirundo rupestris 30 30
H. rustica 10 20 10 15 500 20 15 6 596
H. daurica 20 20
Delichon urbica 10 50 40 5 120 1 20 20 8 274
Anthus campestris 2 2
Motacilla flava 8 25 80 2 5 5 125
M. alba 10 10
T. troglodytes 1 1
Erithacus
rubecula 2 1 4 5 12
Phoenicurus
ochruros 2 12 14
0. oenanthe 3 3
Turdus merula 9 10 19
T. philomelos 4 4
Acrocephalus palustris 5 2 7
A. scirpaceus 5 2 1 8
A. arundinaceus 3 2 2 7
Sylvia nisoria 1 1
S. curruca 1 1
S. communis 1 1
S. atricapilla 2 4 6
Phylloscopus sibilatrix 3 3
Ph. collybita 1 1
Regulus ignicapillus 8 8
Muscícapa striata 2 2
Panurus
biarmicus 4 4
Aegithalos caudatus 9 9
Parus palustris 7 3 10
P. cristatus 7 7
P. ater 4 4
P. caeruleus 2 1 4 6 13
P. major 1 5 8 20 3 39
Sitta europaea 4 2 3 9
Oriolus oriolus 6 1 1 2 10
Species Observant points Total
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Lanius collurio L. minor Garrulus glandarius Pica pica Corvus monedula C. frugilegus C. cornix C. corax Sturnus vulgaris Passer montanus P. domesticus Fringilla coelebs Carduelis chloris Carduelis carduelis C. cannabina Coccothraustes coccothraustes Emberiza citrinella E. hortulana E. calandra
10 10
40 150
50 2
1 2 6
5
30 2 1
7 10 2
2 3 1
15
15 6 2 10
70 2 50 15 30 7 5
20
10 15
6 2
5 2000
20
20
1000 10 2 20 1
4 2
5 2
55 100
21 7
20 44 46 150 6 2
3125 81 146
13
14
30 2
12 16 1
155
Total
54 356 384 12 68 639 369 4435 262 456 336 328 499 3294 2693 69 14254
Results and discussion
Check observations before the solar eclipse
During the studies on August 10th and the morning hours of August 11th, before the beginning of the solar eclipse there were no diversions from the normal behaviour and activity of birds at that time of the day: feeding, watering, water and dust bathing, resting, cleaning of plumage, roaming in the area, laying in supplies and the still breeding birds were protecting their nesting territories, displaying, courting, copulating, taking care of young and so on. The diurnal activity of some of the recorded birds from waking up till falling asleep is as follows: Great Tit - 0614-1940; Collard Dove - 0618-21*4; European Nuthatch -
0619-2010; City Pigeons - 0625 - 2 125; House Sparrow - 0618-2115. Sometimes
conflicts arose between separate individuals in the flocks — a common thing in the gregarious life of birds. Aggressive behaviour was observed when the birds
found food or visited the feeder simultaneously. The quarrelling individuals de-
monstrated mainly the combine poze "threat-readiness for escape". At most of
the time all finished without any fights. As a rule the birds activity decreased with the increasing of sunlight and the warming of the air. Most of the birds rested during the hottest part of the day.
Fig. 1. Observant points, where the studies of birds' behaviour during the solar eclipse on August 11, 1999 were performed.
1 — The ornithological field-station "Rupite". 2 — To the west of the town of Pernik. 3 — Sofia, the garden of the Royal Palace. 4 — Sofia Zoo. 5 — The park of the University of Forestry. 6 — The Iskar Gorge, between Kunino and Karlukovo. 7 — The Vaklinski branch of Durankulak Lake. 8 — Southeastern part of Durankulak Lake. 9 — Between the camps Kosmos and Krapets. 10 — To the southeast of Durankulak Lake. 11 — To the south of Cape Shabla. 12 — Cape Kaliakra. 13 — The old town of Nesebar. 14 — The ornithological field-station "Atanasovsko Lake". 15 — Northwestern part of Atanasovsko Lake. 16 — Central Rodopi Mountains, by the village of Stoikite.
Recorded changes in birds behaviour during the eclipse
Birds did not react during the first phase of the solar eclipse, when 25% of the sun were shaded. They behaved like in cloudy weather. Birds do not feel in advance the solar eclipse as they react for example to the movements of the earth crust preceding the earth-quakes (Nankinov 1977).
When half of the sun was covered the birds and the other animals started reacting (Fig. 3). The eclipse influenced them through the fast change of light, temperature, probably the magnetic field and some other abiotic factors. The birds reactions to the solar eclipse are strictly individual. These reactions have no species, aged or sexual character. Their behaviour when 75% of the sun were covered may be characterised as high excitedness or confusion. In some individuals these reactions were short and passed away (the birds calmed down) soon after the sun was uncovered by the moon and the light increased. In other individuals these reactions continued till the end of the eclipse and even after that.
Immobilisation and break down of the activity appeared in greater part of the birds and some of them fell asleep when the sun was shaded and the light decreased strongly in the zone of the total solar eclipse as well as in forests and
parks in the zone of the partial one. There the reactions were easiest to observe. Before the sun was shaded completely we recorded a movement among almost all passerine birds, which after that went to their roosting places. The wood birds felt the influence of the solar eclipse most strongly. In comparison to the petrifeel birds, they were silent and did not fly. The begging calls of the young birds decreased and stopped.
August 12th
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August 11th
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August 10th
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a
lb
-ГП-p-i r-f4~1~i-)~l~n ,
7 8
9 10 ! 1
13 1/1
16
17 18 19 20 21
Fig. 2. The rate of visiting feeder by birds before the solar eclipse (August 10), in the day of the solar eclipse (August 11) and after the solar eclipse (August 12).
There was a large scale of reactions in the behaviour of Herring Gulls. The first sign of alarm were recorded in Nesebar after 1300, when the sun was half covered. After that some of them flew in groups of 4-5 birds towards Cape Emine, where a roosting existed at that time. When 75% of the sun were hidden a flock of Herring Gulls alighted on the rocks. Some of them started cleaning their plumage, others were in the water or were picking seaweed on the beach. The withdrawing of flocks towards their roosting continued. A sharp change in their behaviour appeared at 1355 just before the sun was hidden completely. About 250 gulls began circling and cawing over the town. This behaviour of a greater part of the population was an acoustic accompaniment of the occurring stress situation. Only a big danger may cause such group panic of birds, united in flocks. However during these sound communications and visual demonstrations, there were individuals taking baths, picking seaweed and some fell asleep. The situation got back to normal about 15 min after the maximum of the solar eclipse, when the light increased. In the zone of the total solar eclipse by Durankulak Lake the flocks of Herring (and Mediterranean) gulls, which were flying mainly to south after 1335
Рус. орнитол. журн. 2001 Экспресс-выпуск № 142 о/Г ]
Fig. 3. Characteristic reactions of birds during the different phases of the solar eclipse.
started flying backward (probably towards some roosting places) and some of them prepared for sleeping on the sand by the lake. At 14 , when it was completely dark, some of the gulls tried to alight on the reeds in the lake, other flew away towards the sea, where the gulls and the Pygmy Cormorants flew chaotically till 1420. At the time of maximum solar eclipse the Herring Gulls from the Cape Kaliakra flew towards their roosting places on the adjacent rocks, but still not reaching them the sun appeared. The birds were rather confused. They were not prepared for such phenomenon and their reactions were inadequate. After a continuos flying
л г
in the air around 14 although very scared the Herring Gulls returned to their places. They calmed down and began feeding just before 1500. At the same time individuals of different wader species (Little Ringed and Kentish Plover, Grey Plover, Sanderling, Ruff, Common Sandpiper) were calm and rested on different places on the shores of the reservoirs. As usual, the Great Crested Grebes were feeding in the sea. The behaviour of birds of prey was as usual, although they had to stop hunting and migrating during the maximum of the solar eclipse because of the darkness. The soaring birds (White Storks, Honey Buzzards, Short-toed Eagles) were recorded in the zone of the total solar eclipse till 1400, e.g. before the maximum. A flock of 200 White Storks flew from north over the Cape Kaliakra at 1330. They continued their flight over the sea, but soon they changed the flight direction to southwest and probably alighted on the shore by the town of Kavarna before the sun was completely shaded. A Kestrel and a Montagu's Harrier passed in the same direction. The bird migration continued without interruption in the zone of the partial solar eclipse.
We did not observed any changes in the behaviour of Quails. The males were displaying, and their song was heard during the whole study period, including the time of the total solar eclipse. The behaviour of the Red-backed Shrike was normal too: signals of alarm and movement of tail, hunting from the air and on the ground, interspecies form of aggression and protection of territory. After 75% of the sun were covered anxiety and excitement arose in the family flocks of the House Sparrow as it happened every evening. The reaction of the Tree Sparrows was similar. The European Bee-eaters reacted in a different way. Their migration over Bulgaria continued without breaks in the zone of the partial solar eclipse. There were no changes in behaviour and migratory rhythm of birds. Some of the European Bee-eaters in the zone of the total solar eclipse got confused and prepared for roosting. Some individuals were restless. The passing flocks alighted and towards 1400 they went roosting too. However, other individuals did not show any anxiety. The swallows (Sand and House Martins, the Swallow) also prepared for roosting in the time of the total solar eclipse. Just before the eclipse some Turtle Doves were displaying, others alighted in suitable heads of trees and prepared for roosting, and third — united in flocks flew towards the confirmed roosting places. In Sofia, the anxiety during the maximum of the solar eclipse was about 10 min. for the European Nuthatch (1357-1405), which after that continued visiting the feeder. It was from 1356 to 1412 for the Tree Sparrow, about 20 min (1405-1424) for the Great Tit and the House Sparrow, from 1405 to 1450 for the Blackbird and 1 hour (1345-1445) for the Collared Dove.
The changes in the bird behaviour were the slightest in the open habitats in the zone of the partial solar eclipse. The eclipse was like a cloudy day on the Atana-
sovsko Lake, where we recorded 5987 individuals of 40 species. However there were reactions but only at the time when the sun was completely hidden (1400-1415). The White Pelicans dispersed in the lake started gathering in groups. Some flew towards Vaja Lake, where they were roosting. The Black-headed Gulls and the Lapwings also gathered in groups. The Redshanks were calm until that moments, flew off with shrieks. The Swallows behaved for a while like at sunset, flying low over the reeds. After that they continued feeding their young in the nests. The rest passerine birds inhabiting the lake were most sensitive — at that time they stopped flying, singing and feeding their young. The situation returned to normal about 1430-1445. We did not recorded any changes in the behaviour of the other birds in the lake (herons, ducks).
In the most peripheral zone of the eclipse in Southwest Bulgaria, on the field-station "Rupite", the activity of the sparrows (House and Tree Sparrows), the swallows (Swallow and House Martin) and some other passerine birds decreased in the time of the maximum solar eclipse.
During the solar eclipse the aggressive behaviour decreased or was lacking in most of the studied species. This happened may be because for a short time the conditions for increasing of activity and feeding became more favourable — the fatiguing bright sun disappeared, the temperature and light dropped down. We recorded signs of aggression only in the behaviour of the Jay and Raven. S.Kumar (1981) wrote about increased aggressiveness of the Little Egrets during the solar eclipse in India in 1980. The Little Egrets were producing more tinkled sounds and were the originators of many fights. At the same time the Cattle Egrets were less noisy and aggressive. The main purpose of the bird song is to attract a mate and for protection of the breeding territory. However the unexpected song of some males during the solar eclipse is an adequate, substitutional reaction, proving the confusion of these individuals. We recorded such reactions in the behaviour of the Scops Owl, European Cuckoo, Turtle Dove, Collard Dove, Great Tit, Marsh Warbler and the Corn Bunting. The reaction of the Chaffinch was very interesting. It reacted with alarm calls and also with so called "rumene"— signal produced by the adult birds before rain, and sometimes at danger. The cleaning and arrangement of plumage, the picking and bathing were the substitutional reactions of some species. We think that the behaviour of the Shags, nesting on the rocky shore between Cape Kaliakra and Tjulenovo, was inadequate too. They were standing on the rocks with stretched wings and were "drying them on the sun", even when it was completely dark. Perhaps they did so because a breeze appeared after the sun was hidden and it could dry their feathers too. Some birds lost their fear of people and sought their protection during the maximum of the solar eclipse. An European Robin stood near the people by a chalet in Rhodopi Mountains for almost an hour (after 1400).
The weather was sunny and hot (34-39 °C) during all three days. The birds were decreasing the heat-generating and increasing the heat-releasing with lessening of the diurnal activity, bathing, searching of shade and cool places, with different heat-regulating poses (slightly open wings and bill and others). Their diurnal activity was in inverse proportion to the high temperature and intense sunlight. The temperature dropped down on August 11th after 1303, when 75% of the sun were hidden. At that time in the course of half an hour the temperature
dropped down with 8°C in the Iskar Gorge and reached a minimum of 27.6°С at 1405. On the sea coast the temperature dropped down (under 20 °C) and a strong cool breeze appeared from the sea. The decreased sunshine and temperature during the solar eclipse were a temporal saving of birds from the heat. They created more favourable conditions and stimulated some of the inhabitants of the open areas. The feeding activity of swifts (Alpine and Common) and some of the swallows (House Martin, Swallow, Red-rumped Swallow, Crag Martin) increased as at sunset. Without any interruption during the whole solar eclipse the Alpine Swifts united in flocks were feeding (over Sofia, the Iskar Gorge and on other places). The swallows did the same, but part of them alighted on buildings or rocks and rested. The increased activity of these and some other species during the partial solar eclipse may be in connection with the resumed flight of the insects they fed on. At that time of the year the swarming of small insects take place at sunset and during the solar eclipse on August 11th, when the light and temperature dropped down. At dawn and dusk of the hot August days the city pigeons roamed for feeding between the city centre and the surrounding of Sofia (Nankinov 1982). This roaming almost stopped during the rest of the day. On August 11th with the decreasing of light and temperature (1330) the pigeons resumed their roaming for food and continued till 1500, when the moon uncovered half of the sun. The flights stopped for about 15 min (1355-1410) during the maximum of the solar eclipse. In that case the feeding activity of pigeons corresponded to their activity from 1915 to 2115 and from 625 to 830.
In August, many bird species migrate over the territory of Bulgaria. They fly towards their wintering grounds during the day as well as during the nights. The high night migrations are prevailing. The decreased light at sunset is one of the factors setting the beginning of the migratory anxiety and the night migrations. It is known (Kiepenheuer 1980) that in some birds the migratory anxiety starts at light 1-10 lk. The sharp decreased of light during the solar eclipse on August 11th probably caused anxiety and start of migration of many passing birds on the territory of our country. Probably it influenced stronger the young birds migrating towards the wintering grounds for the first time. The low light during the solar eclipse stimulated the birds with twilight and nocturnal activity. Around the maximum of the solar eclipse the vocalisation of the Water Rail was more intense than at the morning or noon hours. In Sofia, we heard the Little Owl which at the beginning of August usually calls between 300 and 600 a.m.
It is known that birds use the sun as a compass during distant migrations. At daytime the migrants regularly correct their movement orientating from the sun. It is supposed that the birds use the sun-compass orientation when choosing and maintaining the inborn migratory direction (Weltschko 1981). The sudden obstruction of the sun will lead to some confusion of birds. At the same time the inborn vital cycle and migratory direction are programmed in the passing birds and they are influenced by the magnetic filed of the Earth (Griffin 1987). During the total solar eclipse the sun is shaded and the direction of the magnetic field is confused. After the end of the solar eclipse some of the migrants will reorientate, e.g. will correct the mistake and will continued their migration in the right direction. Others will alight on or near the migratory way. May be this is the reason
for appearance of some distant migrants, as the European Robin, Blackcap, Lesser Whitethroat, Spotted Flycatcher, Wood Warbler and Chiff-chaff, in some of the observant points in the afternoon of August 11th and the next day. During the solar eclipse the ultra-violet emit which the passing birds may use as a trustful orientation point also decreased (Liepa 1986).
May be we must mention about the recorded changes in the behaviour of the cadge birds and some other animals during the solar eclipse. The parrots (of different species) in the Sofia Zoo decreased the vocal communications an hour before the maximum, e.g. when 50% of the sun were shaded. After that they gathered in groups and prepared for sleeping. At 1330 a complete hush occurred and towards 1345 the birds were sleeping. The ducks fell asleep too. Only the hens were worried and the Holland cocks were crowing. The birds gradually awake till 1430 when half of the sun was released. Bats (Chiroptera) did not leave the caves in the Iskar Gorge, probably because there they did not record the sudden but temporal change of light during the solar eclipse. Out of the same reason birds and other animals kept in closed, dark premises did not react to the solar eclipse. The Big water frogs Rana ridibunda in the lakes of north-east Bulgaria started croaking for 2-3 min considerably early before the solar eclipse (1315-1330). They were very active between 1400 and 1415 in other parts of the country too. At that time the butterflies (Lepidoptera) stopped flying. Frogs and butterflies behaved in the same way at dusk or in cloudy weather. The Field Crickets Grullus campestris started whistling at the maximum of the solar eclipse.
Residual reactions in birds behaviour after the solar eclipse
Most of the passerine birds were "sleeping" in the first minutes after the maximum of the solar eclipse. There were no any sounds or movements. The Yellow Wagtails roosting in the reeds of Durankulak Lake, towards 1414 started flying off in groups with the characteristic call as they do every morning. Some young individuals were completely disorientated and did not know what to do. The swallows left the roosting later at 1426 and the European Bee-eaters at 1430. We adduce these observations to stress that birds gradually relieved the influence of the past solar eclipse. When restoring their normal diurnal activity some individuals also reacted with signals of alarm. The Chaffinch reacted again with "rumene". We recorded Ravens chasing in the air and looping with loud caws. On the next morning there were no any diversion of the time and way of waking and the beginning of the diurnal activity of greater part of the species. Birds visited the feeder equally on August 10th, 11th and 12th. However there were a certain drop in the feeding activity after the maximum of the solar eclipse (Fig. 2). Although the light increased the birds were somewhat confused when feeding. In the evening they stopped feeding half an hour earlier. The past solar eclipse has destroyed the rhythm of feeding of the birds, because they visited the feeder more frequent in the morning of the next day /August 12th/.
The solar eclipse led to local movements of flocks and single individuals, and their appearance in neighbouring places, where they were absent before that. Therefor an Eleonora's Falcon, the Stone Curlews, Black-headed Gulls, Common and Sandwich Terns, Long-eared Owls, Scops Owls, European Cuckoos, Mag-
pies, Great Tits and other species appeared in some of the observant points after the solar eclipse. We observed certain changes in flight-direction of some European Bee-eaters. After the solar eclipse the flocks which have been roosting in Durankulak Lake flew off to west although that at that time of the year the migration along the Bulgarian Black Sea coast is to southeast.
Conclusions
After generalising the results from the studies of birds behaviour during the solar eclipse in Bulgaria on August 11, 1999 we made the following conclusions:
1. Birds cannot predict the solar eclipse, e.g. there are no genetic mechanism in their bodies for feeling in advance the beginning of this natural phenomenon.
2. The solar eclipse influences the birds (and all living creatures) through the fast change of light, temperature, magnetic field and probably with some other abiotic factors.
3. Birds behaviour before the setting of the maximum of the solar eclipse and after it is identical with their behaviour when getting cloudy and clearing up, at sunset and sunrise.
4. The first changes in birds behaviour appear when the sun is half hidden. The maximum solar eclipse has an suppressive effect on the living creatures. So the birds reactions are more strong and intense at that phase.
5. The birds reactions to the solar eclipse are strictly individual. Birds of one and the same species, sex and age may have different behaviour. Some are rather confused and excited, others have substitutional reactions, third — fall asleep. Some individuals are surprised by this natural phenomenon, they are stressed and scared, and react inadequately.
6. The behaviour of the individuals in the zone of the partial solar eclipse depends on the concrete area, habitat. The inhabitants of dense parks or forests stop moving and occupy the roosting places, because the light there drops and it becomes rather dark. The birds in the open areas, where the light is more, may only decrease their diurnal activity.
7. The partial solar eclipse (the lower sunlight and temperature respectively) creates more favourable conditions during the hot sunny day and stimulate the inhabitants of the open areas. Their feeding activity increases and they start their feeding migrations.
8. Birds orientate by the luminaries, the magnetic field of the Earth and others during their seasonal migrations. The obstruction of sun and the occurring changes in the magnetic field may lead to a certain confusion, drifts from the migratory route and even ceasing of the migration.
9. Some small and temporal breaks in the rhythm of the diurnal activity of birds, possible drifts from their migratory route or little local movements can be the results from the solar eclipse.
Acknowledgements
The authors express their gratitude to Veselina Kavrakova, Elena Foteva, Liljana Todorova, Kalina Tsvetkova, Teodora Ivanova, Dimitar Uzunov, Dimitar Kantardjiev, Alexander Dutsov, Tihomir Stefanov, Ivan Hristov, Stanislav Shurulinkov, Petar Podlesnii, Рус. орнитол. журн. 2001 Экспресс-выпуск № 142 r\fJl
Äsen Rogev, Rosen Tsonev, Dimitar Avtanski, Tsvetan Zlatanov, Bojidar Tratkov, Valentin
Vutov, Biser Budinov, Metodi Bodiov, Stanislav Kanev and to all other colleagues and
fliends, who helped us during our studies of birds behaviour during the solar eclipse on
August Uth, 1999.
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Проучвания върху поведението на птиците по време на слънчевото затьмнение
на 11 август 1999 година
Димитър Нанкинов, Светла Далакчиева, Борис Николов, Петър Шурулинков, Константин Попов, Светлан Кирилов, Катерина Зарева, Борислав Борисов, Георги Стоянов, Николай Нанкинов, Николай Минчев, Диньо Кючуков, Ивайло Николов, Радослав Станчев, Евгени Ганчев
Проведени са широкомащабни проучвания, организирани от Българската орнитологическа централа, по единна методика в 16 пункта на България. Наблю-давани са 14 254 екз. от 133 вида птици. Установено е, че птиците не могат да предсказват слънчевото затьмнение. В техния организъм няма генетически зало-жени механизми, които предварително да усещат настъпването на това природно явление. То въздейства върху организмите чрез бързата промяна на осветлението, температурата, магнитното поле и вероятно чрез някои други абиотични факто-ри. Поведението на птиците преди настъпването на максималното затьмнение и след прекратяването му в повечето случаи е идентично с това при заоблачаване и изясняване на времето, при залязване и изгряване на слънцето. Най-ранните промени в поведението на птиците се забелязват в периода, когато слънчевия диск е закрит наполовина. Реакциите на птиците на слънчевото затьмнение са строго индивидуални. Птици от един и същи вид, пол и възраст могат да имат различно поведение при затъмнението. В зоната на частичното слънчево затьмнение поведението на индивидите зависи и от конкретната обстановка, от местообитанието, където живеят. Частичното слънчево затьмнение (респективно намаленото слънчево греене, захлаждане) създава по-комфортни условия през горещия летен ден и действа стимулиращо върху някои обитатели на откритите
пространства, при конто активността на хранене нараства и се възобновяват хра-нителните им миграции. Като следствие от преминалото слънчево затъмнение могат да бъдат само някои леки, временни нарушения в ритьма на дневната ак-тивност на птиците, евентуални отклонения по прелетния им път или незначи-телни локални премествания.
Ю G3
ISSN 0869-4362
Русский орнитологический журнал 2001, Экспресс-выпуск 142: 369-370
Встреча среднего пёстрого дятла Dendrocopos medius в г. Печоры (Псковская область)
А.В.Бардин
Кафедра зоологии позвоночных, Биолого-почвенный факультет, Санкт-Петербургский университет, Университетская набережная, 7/9, Санкт-Петербург, 199034, Россия
Поступила в редакцию 25 марта 2001
4 октября 1980 средний пёстрый дятел Dendrocopos medius около часа вертелся в саду на углу улиц Псковская и Новая в г. Печоры (57°49' с.ш., 27°37' в.д.). Его явно привлекла деятельность больших синиц Parus major и болотных гаичек Parus palustris, таскавших подсолнечные семечки с кормушки на подоконнике. Однако прилететь на окно он так и не решился. Это была единственная встреча вертлявого дятла в окрестностях Печор за период моих наблюдений с 1965 по 2000 годы.
В своей сводке А.С.Мальчевский и Ю.Б.Пукинский (1983, с. 478) пишут: "Все сообщения о якобы имевших место встречах средних пестрых дятлов на территории Ленинградской обл. были ошибочными: их путали с молодыми большими пестрыми дятлами. Из достоверных указаний можно сослаться лишь на сообщение Н.А.Зарудного [1910], отмечавшего, что в конце прошлого столетия несколько экземпляров этого вида было добыто в гнездовой период в окрестностях Пскова". У Н.А.Зарудного (1910, с. 99) читаем: "Picus medius, L. Очень редкая гнездящаяся птица Псковской губернии. Один экземпляр, добытый г-ом Даниловым в собственном имении в Торопецком уезде в VI. 1893 г., имеется в моей коллекции. Около с. Нестеры (Островский уезд) 10.VI.1895 г. я добыл один экземпляр в лиственной роще. В том же году один экземпляр был убит В.П.Гиллейн-фон-Гембиц в VII в окрестностях Пскова". В сводке "Птицы Западной Палеарктики" (Cramp 1985) в гнездовую часть ареала вертлявого дятла включена часть Псковской обл. на север до Пскова, очевидно, на основании данных Н.А.За-рудного. В последнем списке птиц Псковской обл. (Урядова, Щеблыкина 1993) Dendrocopos medius приводится в качестве очень редкой гнездящейся птицы, хотя на протяжении XX в. никаких сведений о нём с территории области в орнитологической литературе не появлялось.
