Page 138 - Panuccio2012

Number of W. Hone 2000

1500

1000

500

654 Zoological Studies 49(5): 651-6506 (2010)
continge7:n20c-y9:1t9a9b:2l0e-1: 1χ:1291=1:2707-1.38:199,13d:2.0f.-1=5:1291,5:p20<-170:2.001)
respectively). Western Honey Buzzards migrated

across the 3 sites mainly during prevailing westerly and during low ratThimere ptehriaodns high barometric
winds: the derived average number of birds pressure (contingency table: χ2 = 206.97, d.f. = 2,
counted per hour of observation was 15.1 ± 1.1 p < 0.01. Fig. 4). Although the strength of the

(SE) with westerly winds vs. 3.6 ± 1.9 (S.E.) with westerly winds did not affect migration counts,
easterly winds (z = 7.75, p < 0.01). Barometric the proportion of migrants was significantly higher

pressure and the strength of the westerly winds along the ea7s:t2e0r-9n:1c9orridor9d:2u0-r1in1:g19strong11w:2e0-s1t3e:1r9lyProNpuortmiboenrofofW.W.HHoonneeyyBBuzuzzarardsds
Number of W. Honey Buzzards 2.2, d.f.
did n25o0t0significantly affect migration counts; the w ind2s500(c ont1in3:g20e-1n5c:1y9 table15::2χ02-17=:209 pressure = 2,
derived average number of birds counted per p <1000.0%1; Fig. 5) and low barometric (Fig.
hour20o0f0 observation was 12.6 ± 3.2 (S.E.) with 5; co82n00t%0i0ngency table: χ2 = 208.8, d.f. = 2, p < 0.01).

low 1b5a0r0ometric pressure vs. 11 ± 3.8 (S.E.) with 1500

whiigthh10wb0ae0raokmwetersicteprrlyeswsuinrdes, and 17.4 ± 1.1 (S.E.) 60%
vs. 13.5 ± 1.1 (S.E.) 1000
40% DISCUSSION
500
with s50tr0ong westerly winds. Weather conditions
2W0%0ind direction and time of day significantly
for soa0ring flight apparently were better during Aa fsf eec0xt%epd7e:2c0mt-e9i:d1gE9,ar9sa:t2teht0ir-eon11n:p19ec1oa1C:ku2e0nn-ot1rt3asf:l1Cm9i 1noi3rgr:i2odr0oau-1rstr5i:o1s9nt1u5Wo:d2c0ey-sc1t7eua:r2rrn0reead.
twheeakprwo7pin:2od0r-s9ti:1oa9nn9:d2o0-fh11ibg:1ih9rd11bs:2a0pr-o1a3ms:1s9ei1tn3r:ig2c0-lp1o5rw:e19es1sr5u:2trh0e-a17ns:2i0nthcee during the afternoon when thermals were at
observation posts or at eye level was higher during their strongest, andTimtheepreeriofdosre migrants were
strong (> 20 km/h) ratThimere tpheariondsweak winds (Fig. 4;

able to optimize soaring flight and increase their

ProportionNoufmWb.erHofneWy.BHuoznzeayrdBsuzzards PropoPrrtioopnorotfionW.ofHoWn.eyHoBnuzezyarBdusz z ards Up Down

2500 7:20-9:19 9:20-11:19 11:20-13:19 100% 7:20-9:19 9:20-11:19 11:20-13:19
2000 13:20-15:19 15:20-17:20
10105%00 80% 13:20-15:19 15:20-17:20

10600%%

810%00 8400%%

605%00 6200%%

40%0 400%% winds Weak bwainrCodmesnettrrLaicol pCwreobsrarsirduoormersetric pressure
20%7:20-9:199:20-11:1911:20-13:1913:20-15:1915:20-17:20 EasteHrnigh Western
200%%Strong
0%
Eastern TimCenpterariloCdosrridors Western

Fig. 2. Variations in the daily patterns of migration (solar time) Fig. 3. Variations in the daily patterns of migration (solar time)
of Western Honey Buzzards through the Marcellinara Isthmus. along the western, central, and eastern corridors.

PrPorpooprtiorotinonofofW .W.HHoonneeyyBBuuzzzzaarrddss 7:20-9:19 9:20-11:19 Up11:20-1D3o:1w9n PrPorpooprotirtoinonofofW .W .HoHnoenyeyBuBzuz za radrsds Eastern Central Up WesDteorwnn
13:20-15:19 15:20-17:20
110000%% 110000%%

8800%% 8800%%

6600%% 6600%%

4400%% 4400%%
2200%%
2200%%
0%
00%% wiEndasstWerenak bwainrCodmsenettrrLaicol pwCreobsrarsirduoromersetric prWesessutreern Strong 0wS%etrsotenrglyWwweinianddksswWeHseigtHaehkirglybhwawibnriaonddrmsosmeterLitcroicpwLrpoerbwesassrbusoaurmerroeemtreictripcreprsessusruere
Strong High

Fig. 4. Proportions of Western Honey Buzzards passing high Fig. 5. Proportions of Western Honey Buzzards passing along

.ofHoWn.eyHoBnuezyz aBrudzsz ardsand low with strong and weak winds and withUphigh anDdolwown the eastern, central, and western corridors during periods
barometric pressure. of strong and weak westerly winds and during high and low

100% Eastern Central Western barometric pressure.. Honey Buz z ards Eastern Central Western
18000%% 100%

6800%% 138 80%

4600%% 60%

2400%% 40%