Ismar et al. • MIGRATION OF AUSTRALASIAN GANNETS 
123 
FIG. 2. Time of year over weekly means of longitude during the non-breeding period for three adult gannets equipped 
with geolocators at Cape Kidnappers Plateau Colony; A08 male Australasian Gannet, A77 female Australasian Gannet, B60 
male Cape Gannet X Australasian Gannet. 
in previous geolocation studies of seabirds 
(Phillips et al. 2004, Shaffer et al. 2005). 
RESULTS 
Both Australasian Gannets and the M. capensis 
x M. senator hybrid migrated across the Tasman 
^a, spending between 2 (hybrid B60) and 
4 months (Australasian Gannets A08 and All) 
in Australian and Tasmanian coastal waters 
(Pig- 2) before returning to the same subcolony 
at Cape Kidnappers (Fig. 1). These wintering 
areas were straight-line distances of 3,450 km 
(A08) and 2,350 km (All and B60) from the 
gannetry. Distances covered during migration 
between breeding seasons were at least 
1 3,000 km for A08 (Fig. 1A), 5,800 km for All 
(Pig- IB), and 10,000 km for B60 (Fig. 1C). 
The male Australasian Gannet A08 (Fig. 1A) 
Passed the North Cape (176.48° E, 32.66° S) on 
!3 March 2008 and subsequently crossed the 
Tasman Sea to reach Bass Strait (147.73 E, 
40.07° S) on 15 April 2008, from where it 
continued to the area of Kangaroo Island, South 
Australia, in the Great Australian Bight (139.79° 
E, 38.24° S; 22 Apr 2008). This bird spent 93 days 
in this region, before it passed Bass Stiait again on 
24 July 2008. A08 appeared to follow the 
Australian East Coast somewhat northward 
(153.97° E, 34.71° S on 14 Aug 2008) before it 
crossed the Tasman Sea again and reached Cook 
Strait (174.77° E, 40.88° S) on 21 August 2008. 
The bird subsequently left New Zealand waters a 
second time to fly to the East Australian Coast 
(154.06° E, 28.29° S; 28 Aug 2008), via North 
Cape New Zealand (174.39° E, 35.20° S; 21 Aug 
2008). It followed the Australian coastline south 
to Bass Strait (150.35° E, 42.76° S; 30 Aug 2008), 
and flew across the Tasman Sea taking a route via 
Stewart Island (167.16 E, 50.1° S; 08 Sep 2008) 
to its breeding location. This second trip across 
