17.05.2021 – Scouting the surface

Gusts of wind were lightly ripping at the surface of the Atlantic as our Stenella drove out of Calheta for our morning tour. Our spotter turned his sharp eyes to the waters further east, a few miles outside Ponta do Sol and saw an aggregation of several seabirds so we set off to investigate. The birds circling the area were mainly Cory’s Shearwaters (Calonectris borealis), an estival breeding species in Madeira with colonies returning every summer to nest in the archipelagos coastline. These long-lived sea birds know which dolphins to follow and, today, they were following a large group of Atlantic spotted dolphins (Stenella frontalis). Despite the incredible size of the pod, we saw the birds way before we saw the dolphins which emphasises how important these birds are for our team when it comes to finding cetaceans.

Not only are marine birds traditional aerial participants in large feeding situations involving several species (an event which easily attracts attention from above), they also cruise over the ocean searching for these events so each bird is essentially a scout for all the others to gain some feeding advantages. The gliding, bouting flight of the shearwaters allows to this for hours on end and conduct their searches just above the surface of the water.

Our spotter soon found another situation near Ribeira Brava; this time involving a group of voracious Yellow-legged gulls (Larus michahellis) that were pursuing prey in the company of Short-beaked common dolphins (Delphinus delphis). Whilst the spotted are usually encountered in areas with larger depths,  common dolphins prefer the waters closer to shore meaning these feeding situations can easily be admired from the coastline.

By Paula Thake

Sightings of the day

Ribeira Brava

14:30 No sighting

Stenella

10:00 Atlantic spotted dolphins, Short-beaked common dolphins