THE PTERODROMAS
Scientific name
Madeira Petrel / Zino’s Petrel
(Pterodroma madeira)
Desertas Petrel
(Pterodroma deserta)
Taxonomic status | Distribution |
Population
Madeira Petrel / Zino’s Petrel
Endemic species of the Madeira Island.
Population estimated at 65 to 80 pairs.
Desertas Petrel
Endemic species of Bugio - Desertas Islands.
Species recently separated from the Cape Verde pterodroma (Pterodroma feae), based on genetic studies (2009).
Population estimated at 160 to 180 pairs.
conservation status
Madeira Petrel / Zino’s Petrel
"Endangered” - by the IUCN Red List and the Red Book.
Desertas Petrel
"Vulnerable" - by the IUCN Red List and the Red Book.
Description
Madeira Petrel / Zino’s Petrel
Pterodromas are species of the Procellariidae family. In both species the plumage is similar, with the wings and back being dark, almost black. The belly is whitish and the tail grey. It is 32-34 cm long, with a wingspan of 80-86 cm and weighs approximately 200 g.
Desertas Petrel
They are morphologically different in size. The Desertas Petrel is larger and has a more robust bill. It is 33-36 cm in length, 86-94 cm in wingspan and weighs about 300 g. Genetically they are very distinct and do not share a common ancestor.
Habitat
Madeira Petrel / Zino’s Petrel
The Pterodromas are pelagic seabirds that spend a large part of its life cycle in the open sea. This species breeds in the Eastern Mountainous Massif, above 1600 metres altitude on steep and inaccessible cliffs of native vegetation (mostly herbaceous) and in a good state of conservation.
Desertas Petrel
The majority of the population breeds on the southern plateau of Bugio, in an area of inaccessible and restricted herbaceous vegetation of less than 20 ha, at an altitude of around 380 metres.
reproduction
Madeira Petrel / Zino’s Petrel
From the end of March / early April, the Madeira Petrel starts visiting the nesting areas. In a first phase the preparation of the nest, then mating, pre-laying exodus and return to the colony. This is followed by the stages of laying (between mid-May and the end of June), incubation, hatching and the departure of the juveniles, which lasts until October. Both species excavate their nests on the ground, where the vegetation cover is in a good state of conservation and the soil sufficiently stable.
Desertas Petrel
The Desertas Petrel arrives at the colony in June, to begin nest cleaning, mating and copulation. After the pre-posture exodus the first eggs are laid in mid-July. Hatching takes place from mid-September and the juveniles leave the nest from mid-December.
Behavior
Madeira Petrel / Zino’s Petrel
They have mostly nocturnal behaviour. They come to their nests on land after sunset, returning to the sea before sunrise.
Desertas Petrel
The behaviour is similar between species.
Diet
Madeira Petrel / Zino’s Petrel
Both species feed on cephalopods and mesopelagic fish. In the wintering season, the Petrels travels far from its colony, and some areas are known to be used on the Brazilian coast, around the Cape Verde archipelago, on the southeast coast of the USA and in pelagic waters in the central South Atlantic.
Desertas Petrel
Recent studies show that during the breeding season Petrel’s travel long distances in a single journey to feed, up to about 12 000 km in the case of the Desertas Petrel.
legal status
Madeira Petrel / Zino’s Petrel
Listed in Annex I of the Birds Directive and Annex II of the Bern Convention. The whole nesting area is identified as: see Intervention Area
Desertas Petrel
Listed in Annex I of the Birds Directive and Annex II of the Berna Convention. The whole of the nesting area is identified as: see Intervention Area
THREATS
Habitat degradation and consequent risk of nest destruction by fire in the Mountainous Massif
(Madeira Petrel)
Following the removal of the wild goats and sheep in 2005, the area showed a slow but steady recovery. However, this habitat restoration was interrupted in 2010 when a strong fire hit the area. In that year, 80% of active nests were destroyed, in which 98% of juveniles were killed and an undetermined number of adults also died.
The fire created the conditions for the establishment of invasive plants (e.g. broom), which in turn are much more prone to fire than native vegetation. Nowadays, against a backdrop of climate change and increased fire risk, this is a major concern. Another limiting factor related to invasive plants is the reduction of suitable nesting areas.
Habitat degradation caused by extreme weather events, such as localised heavy rainfall leading to flooding and landslides
(Desertas Petrel)
The breeding habitat of the Desertas petrel is slowly recovering, but in the last 8 years a high number of nests have been damaged by localised heavy rainfall. These events, associated with climate change, are likely to become more frequent. This has been an important factor in the failure of breeding.
Predation by invasive introduced species
(Madeira Petrel)
The introduction of terrestrial predators by man, such as rats and cats, has become the greatest threat to seabirds, especially in island habitats, severely affecting the reproduction and continuity of species. Due to predators, many seabirds are moving to more inaccessible locations.
The current predator control programme in the Madeira Petrel nesting area has been running since the late 1980s, probably one of the oldest in the world. Over the years this control has ensured the conservation of this unique species, through the creation of predator exclusion zones and the effort of field work in trap monitoring. However, almost every year there are recorded deaths of birds by predation, a result of the constant presence of these predators in the area and their resilience to the control scheme.
Light pollution on land (Madeira Petrel)
and at sea (both species)
Another very significant threat affecting both species is light pollution. In Madeira, when leaving and reaching their nests, the seabirds have to fly over populated coastal areas. There is a strong impact on the populations of these groups of petrels, mainly on the survival of juveniles. Every year, chained petrels (~ 1-3) are found in urban centres. Light pollution at sea, mainly associated with fishing, is another important potential source of mortality for these species, currently poorly studied.
Human use of breeding areas for recreation and tourism
(Madeira Petrel)
Areeiro is an area increasingly sought after for tourism and mountain activities, posing a serious threat to breeding birds. Walking on the nesting patches recently caused the destruction of a nest and the death of a juvenile petrel in 2019. Night-time activities can cause disturbance to birds arriving at nests due to the torches used. Regulation of these activities and creation of strong awareness campaigns is vital.
Insufficient knowledge about population size and trends (both species)
and location of nesting areas (Madeira Petrel)
The study of the biology and ecology of both species is difficult due to the inaccessibility and remoteness of the nesting areas, associated with weather conditions that can be extreme.
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For the Madeira Petrel, the constant presence of people in the vicinity of the nesting areas, the dispersion of the species to new areas after fires, the lack of knowledge of the location of these areas and the difficulty of prospecting in escarpments are factors that make the study and conservation actions difficult. As for the Desertas petrel, the lack of access conditions and the fact that they remain for long periods in the inhospitable Bugio Island contribute to a relevant lack of information on reproductive success and other data on their biology.
Outdated and unsustainable general monitoring scheme (both species)
The multidisciplinary conservation programme underway since the 1980s has ensured the preservation of these endemic seabirds, but their growth rate has been below that required to make the species resilient to fluctuations that could result in extinction.
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The programme of work carried out (such as monitoring breeding and predator control), highly dependent on human and financial effort, is unsustainable. In this context, it is a priority to modernise this programme with innovative technologies, making it more effective and efficient, as this is the only way to guarantee the self-sustainability of these species.
CONSERVATION
Information available soon.