^_0 500 1,000 2,000Km10° S
20° S
30° S
40° S
50° S
130° W 120° W110° W 100° W 90° W 80° W50° N
80° W 60° W 40° W 20° W 0°30° N
10° N
10° S30° S50° SMAP 7. Murphy’s Petrels nest-
ing on Henderson Island (star)
undertake two types of trips
when off- duty during incubation.
These can be to the south (orange
shades, darker shading indicat-
ing more intensive use of the sea
area), or looping trips east of the
colony towards the Humboldt
Current (green shades). Exam-
ples of two anti- clockwise loop-
ing trips are shown as black lines
with black arrows indicating
direction of travel. The averaged
monthly wind speed and direc-
tion over the incubation period
(June– July) are shown by blue ar-
rows in the background. Arrow
size relates to the wind speed,
with higher speeds represented
by longer arrows. These prevail-
ing winds mean that birds on
their anti-clockwise looping trips
benefit from following winds
on both the outward and return
journeys. See page 120. Map repro-
duced with permission. ©Thomas
Clay and Michael Brooke.MAP 8. Trans- equatorial migration and non- breeding distribution of Sooty Shearwaters from Kidney
Island, Falklands Islands, South Atlantic in 2008 and 2009. Red depicts the northward migration, green
the main staging and non- breeding areas and yellow the southward migration. See page 124. Reproduced,
with permission of Inter-Research, from the work cited in Note 17, Chapter 6.