Balearic Shearwater (Puffinus mauretanicus)

Balearic Shearwater

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Puffinus mauretanicus | [authority] Lowe, 1921 | [UK] Balearic Shearwater | [FR] Puffin des Baleares | [DE] Balearen-Sturmtaucher | [ES] Pardela Balear | [NL] Vale Pijlstormvogel


Genus Species subspecies Region Range
Puffinus mauretanicus AO e


Until recently the shearwaters were devided in two genera Calonectris and Puffinus, but based on dna-analysis Penhallurick and Wink (2004) have proposed a splitting of the shearwaters into three genera: Calonectris for the large shearwaters of the Northern Atlantic, the Mediterranean and the waters around Japan, Ardenna for a group of large Southern Hemisphere breeders and Puffinus for the smaller shearwaters such as the Manx’ group, Audubon’s and Little Shearwaters. This new taxonomy is now widely accepted, but not by all and is stil subject of discussion.

Physical charateristics

Medium-sized, rather dark shearwater. Upperparts dark brown contrasting slightly with the dirty, variably marked brown-whitish underparts. Most individuals show dusky undertail coverts and armpits. Similar spp. Easily told from Manx Shearwater P. puffinus by lack of strong contrast between upperparts and underparts. Dark individuals could be mistaken for Sooty Shearwater P. griseus but always show a white belly patch and lack the scythe-like wings and heavier flight of that species.

Listen to the sound of Balearic Shearwater

[audio: Shearwater.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by Miguel McMinn Grivej

wingspan min.: 80 cm wingspan max.: 88 cm
size min.: 32 cm size max.: 37 cm
incubation min.: 50 days incubation max.: 54 days
fledging min.: 70 days fledging max.: 54 days
broods: 1   eggs min.: 1  
      eggs max.: 1  


Atlantic Ocean : East. Puffinus mauretanicus breeds in the Balearic Islands, Spain.


The main part of the population breeds under boulders, in caves and crevices of cliffs, where
census is impossible except by indirect estimates. Some colonies occupy similar habitats in islets.
Little excavation is reported, only a slight hollow in caves with clay ground. There is no
significant material carried to the nest.
Nowadays the species seems to occupy sub-optimal habitats due to human disturbance and
introduced predators. Fossil remains show that important colonies were on the mainland of the
major isles. Breeding places of P. mauretanicus at 500 m far from coast in Cabrera Island has
been described (Araujo et al. 1977). Bone remains have been found in caves far from the coast
but at the present the species is extinct from this island.


The species visit land for breeding from September to late June. Eggs are laid from the beginning of March and the last chicks do not fledge until July. Reproductive success has been measured in three accessible colonies. Results vary from 46 to 77,7 % (the last one after a rat cont rol campaign), with an average of 66,8 % by pair. Females lay a single egg at a nest site (a burrow, a crevice or directly on bare ground) during February-March, and incubation lasts ca. 50 days. Chick
rearing period extends for ca. 65-70 days.

Feeding habits

The species feed mainly on shoaling Clupeiforms. Its diving ability has proven through many observations of flocks performing a pursuit sequence of plunging, diving, running over surface, short flapping flight and plunging again. The species
plunges from 1 or 2 m height (the common height of flying) with open wings, entering the water headfirst. The dives last up to 40 seconds. The maximum depth recorded is 26 m. Capture of discarded fish has also been reported in Balearic waters, though not frequently. Uses of trawler discards appear to be important in the Mediterranean off the Iberian Peninsula during
the breeding season and in the Bay of Biscay during the post-breeding period. Use of mid-water trawls have increased dramatically since the mid 1980’s, and changes in post-breeding distribution can be related. During the breeding season the main feeding areas are on the Eastern Iberian Peninsula coast. Recent displacement northward in their winter distribution has been reported and explained due to changes in the clupeiform abundance

Video Balearic Shearwater


copyright: Stuart Fisher


This species has a tiny breeding range and a small population which is undergoing an extremely rapid population decline owing to a number of threats, in particular predation at breeding colonies by introduced mammals and at-sea mortality as a result of interactions with commercial fisheries. Population models predict an extremely rapid decline over three generations (54 years), qualifying the species as Critically Endangered. However, recent records at sea indicate that this species may not have suffered declines as drastic as previously thought. Should the species have declined at a more moderate rate, or indeed, not at all, this species will warrant downlisting.
Puffinus mauretanicus breeds in the Balearic Islands, Spain. Its breeding population has been recently estimated at 1,750-2,125 pairs and at 1,447-1,927 pairs, both significant reductions from the 3,300 breeding pairs estimated in 1991. However, there has been no exhaustive census due to the inaccessibility of breeding sites and this precludes an accurate estimation of population trends. Up to 70% of the population breeds in cliffs on Formentera and surrounding islets. The remainder of the population are on Mallorca, Cabrera, Menorca and Ibiza, primarily on islets rather than the main islands themselves. In winter, it occurs in the Balearic Sea and on the north-east Spanish coast with most of the population concentrated between Valencia and Catalonia from November to February. Some birds migrate north to seas off the British Isles and the south of the Scandanavian Peninsula.
Balearic Shearwater status Critically Endangered


Not thoroughly known because of identification difficulties. After breeding disperses into Mediterranean, then through Straits of Gibraltar into Atlantic; a few remain around Balearics and off south-east Spain all year. Majority move to Bay of Biscay, some to North Sea (as far as southern Norway) and Irish Sea; others recorded to south in waters off Morocco, some juveniles perhaps wintering off West Africa; vagrants recorded off southern Africa. Most of population leave Mediterranean from May, peaking off Gibraltar late June, and present in English Channel and (mainly western) North Sea July-October (mid-May to December). Thousands congregate to moult off western France June-October, and perhaps also off north-east England; returns to Mediterranean September-November (-March).

Distribution map

Balearic Shearwater distribution range map


Title Modelling demography and extinction risk in the endangered Balearic shearwater
Author(s): Daniel Oro, Juan Salvador Aguilar, Jose Manuel Igual, Maite Louzao
Abstract: Several demographic parameters of Balearic shearwa..[more]..
Source: Biological Conservation 116 (2004) 93-102

download full text (pdf)

Author(s): Ricard GUTIRREZ and Jordi FIGUEROLA
Abstract: The taxonomic status of the Mediterranean Shearwat..[more]..
Source: Ardeola(42)2, 1995 161-166

download full text (pdf)

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