The purpose of the research was to find a time frame for the beginning, duration of maximum intensity, and end of nocturnal bird migration. The research was carried out using photo registration on a radar screen during the spring and autumn seasons of 1999–2001. Examination of the average length of daylight at the beginning of migration and the onset of civil twilight yielded a high correlation factor for both spring and autumn. The results showed that, on average, nocturnal migration began at the onset of civil twilight, that is, half an hour after sunset. The time elapsing between the onset of migration and the maximum concentration of migratory birds averaged about 70 minutes in both spring and autumn. Nocturnal migration usually came to an end within the one and a half to two hours after sunrise. We ascertained the seasonal time shift for the onset of nocturnal migration corresponding to the seasonal time shift related to the approach of darkness. The average times of the beginning, maximum intensity and end of nocturnal migration were found to be related to photoperiodic factors.
REFERENCES
T. Alerstam
1972. Nocturnal bird migration in Skane, Sweden, as recorded by radar in autumn 1971. Ornis Scand. 3: 141–151. Google Scholar
T. Alerstam
1976. Nocturnal migration of thrushes (Turdus spp.) in southern Sweden. Oikos 27: 457–475. Google Scholar
H. Alfia
1995. Surveillance radar data on nocturnal bird migration over Israel, 1989–1993. Israel J. Zool. 41: 517–522. Google Scholar
R. C. Beason
1978. The influences of weather and topography on water bird migration in the southwestern United States. Oecologia 32: 153–169. Google Scholar
F. C. Bellrose
1967. Radar in orientation research. Proc. XIX Int. Ornithol. Congr., pp. 281–309. Google Scholar
F. C. Bellrose
1971. The distribution of nocturnal migration in the air space. Auk 88: 397–424. Google Scholar
H. Blokpoel
,
J. Burton
1975. Weather and height of nocturnal migration in east central Alberta: a radar study. Bird Band. 46: 311–328. Google Scholar
B. Bruderer
1999. Three decades of tracking radar studies on bird migration in Europe and the Middle East. Proc. Intern. Seminar Birds Flight Safety Middle East Israel, pp. 25–29. Google Scholar
B. Bruderer
,
F. Leichti
1995. Variation in density and height distribution of nocturnal migration in the south of Israel. Israel J. Zool. 41: 477–489. Google Scholar
M. B. Casement
1966. Migration at the Mediterranean observed by radar. Ibis 108: 461–491. Google Scholar
L. Dinevich
,
L. Kaplan
2000. Radar observation of bird migrations. Sci. Israel Technol. Advantages 2: 89–93. Google Scholar
L. Dinevich
,
Y. Leshem
,
A. Gal
,
A. Kapitannikov
2000. Study of bird migration by means of the MRL5 radar. Sci. Israel Technol. Advantages 2: 94–104. Google Scholar
W. H. Drury
,
I. C. T. Nisbet
1964. Radar studies of orientation of songbird migrants in Southeastern New England. Bird Band. 35: 42–61. Google Scholar
L. Flock
1970. Radar observation of bird migration at Cape Prince of Wales. Arctic 25: 25–36. Google Scholar
S. A. Gauthreaux Jr
.
1972. Behavioral responses of migrating birds to daylight and darkness: a radar and direct visual study. Wilson Bull. 84: 136–148. Google Scholar
R. R. Graber
1968. Nocturnal migration in Illinois-different points of view. Wilson Bull. 80: 36–71. Google Scholar
R. R. Graber
,
S. S. Hassler
1962. The effectiveness of aircraft — type (APS) radar in detecting birds. Wilson Bull. 74: 35–42. Google Scholar
L. G. Grimes
1977. A radar study of tern movements along the coast of Ghana. Ibis 119: 28–36. Google Scholar
A. Hall George
,
R. K. Bell
1981. The diurnal migration of passerines along an Appalachian ridge. Am. Birds 35: 135–138. Google Scholar
R. R. Hassler
,
R. R. Graber
,
F. C. Bellrose
1963. Fall migration and weather: a radar study. Wilson Bull. 65: 56–77. Google Scholar
D. Lack
1960. Migration across the North See studied by radar. II. The spring departure, 1956–1959. Ibis 102: 26–57. Google Scholar
D. Lack
1963. Migration across the southern North See studied by radar. IV Autumn. Ibis 105: 1–54. Google Scholar
Y. Leshem,
O. Bahat
1999. Flying with the Birds. Yedioth Ahronot — Chemed Books, pp. 51 and 213. Google Scholar
G. H. Lowery Jr
.
1951. A quantitative study of the nocturnal migration of birds. Univ. Kan. Pub. Mus. Nat. Hist. 3: 361–472. Google Scholar
R. E. Moreau
1972. The Palearctic-African bird migration system. Academic Press, London, pp. 26–32. Google Scholar
I. C. T. Nisbet
1963. Quantitative study of migration with 23-centimeter radar. Ibis 105: 435–160. Google Scholar
J. L. F. Parslow
1969. The migration of passerine night migrants across the English Channel studied by radar. Ibis 111: 48–79. Google Scholar
W. J. Richardson
1971. Spring migration and weather in eastern Canada: a radar study. Am. Birds 25: 684–690. Google Scholar
W. J. Richardson
1972. Autumn migration and weather in eastern Canada: a radar study. Am. Birds 26: 10–17. Google Scholar
W. J. Richardson
1978a. Reorientation of nocturnal landbird migrants over the Atlantic Ocean near Nova Scotia in autumn. Auk 95: 717–732. Google Scholar
W. J. Richardson
1978b. Timing and amount of bird migration in relation to weather: a review. Oikos 30: 224–272. Google Scholar
W. J. Richardson
1979. Radar techniques for wildlife studies. Nat. Wild. Fed. Sci. Techn. Ser. 3: 171–179. Google Scholar
W. J. Richardson
1990. Timing of bird migration in relation to weather: updated review. In:
E. Gwinner (ed.).
Bird Migration: Physiology and Ecophysiology. Springer, Berlin, pp. 78–101. Google Scholar
W. J. Richardson
2000. Bird Migration and Wind Turbines: Migration Timing, Flight Behaviour, and Collision Risk. Proc. of National Avian — Wind Power Planning Meeting III. LGL Ltd., Environm. Res. Assoc. King City, Ontario, p. 133. Google Scholar
W. J. Richardson
,
W. W. H. Gunn
1971. Radar observations of bird movements in East-Central Alberta. Canadian Wildlife Serv. Rep. Ser. 14: 17–21. Google Scholar
