Also known in the Alentejo as “hunter-eagle”, the Montagu’s Harrier (Circus pygargus) is the least corpulent of all its Circus congeners that occur in Portugal. The male, with its light grey hue and black extremities, can be mistaken for the Hen Harrier (Circus cyaneus).

Considered endangered in Portugal, this species returns every year to the steppes of Castro Verde and Mértola to breed. But the nests, built on the ground, are highly vulnerable to harvesting and, unfortunately, the population in southern Portugal has been declining over recent years.

Protecting the Montagu's Harrier

The population of the Montagu’s harrier has declined immensely in recent years, it is estimated that it has lost more than 70% of the population. Therefore, a conservation project is underway in Baixo Alentejo, developed by LPN and ICNF- Parque Natural do Vale do Guadiana.

The main reasons that lead to the reduced reproductive success rate are due to mowing and predation. If mowing occurs at the time of spawning, while the eggs are incubating, it is likely that the couple will abandon the nest, as they will have no protection for their chicks when the eggs hatch. In these cases, the field team collects the eggs and finishes their development in captivity. 3 weeks after they hatched, they are relocated to the acclimatisation centre.

When harvests occur with chicks already in the nest, the couple typically does not abandon them. But with the lack of protection afforded by the plantas, the youngsters are easy prey for general predators like foxes and mongoose, or for other birds like storks or eagles.

In this case, the chicks are collected and brought to a structure, in the LPN property in Vale Gonçalinho, where they grow up safely. This is a process of acclimatisation, the aim being that the chicks recognise this location as their point of reference, where they should return when they reach sexual maturity.

The Portugal Wildscapes Conservation Fund has provided surveillance cameras to be placed inside the acclimatisation space to help technicians monitor the young birds’ behaviour. The technicians avoid direct contact with the birds as much as possible, so that they do not get used to human presence.

Would you like to spot a Montagu's Harrier on your next tour to southern Portugal?

Contact us, take a look on our birding tours, or if you prefer travelling on your own, discover our Birding Trail!

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