Something I’m really enjoying about my new journey as a PhD researcher is the opportunity to collaborate in teaching bachelor’s courses. At our university, students of Environmental Sciences have plenty of field courses. I envision nature as the best place to learn, and this bachelor’s scheme seems ideal for it. Plus, for me, it feels organic to learn how to teach in the outdoors.
Last week we visited Sierra Espuña in Murcia for a practical case field session in which students learned some details about managing a well spread population of an exotic herbivore. The aoudad or Barbary sheep (Ammotragus lervia) was introduced for the first time in the Iberian Peninsula at this very place in 1970 as a new species available for hunters. Although threatened along its native distribution in North Africa, the species has since become widespread and abundant throughout the dry southeastern mountain ranges of Iberia, with complex implications for the local environment.
Sierra Espuña aoudad population had been at all time high for many years but recently dropped to few hundreds. The day was foggy, but nevertheless we managed to encounter several herds with up to 25 individuals resting or grazing in several slopes at different distances. We not only tried to tell apart age and sex, but also learned the different approaches at surveying wild ungulates carried out in Spain — by actively looking for them, by walking certain transects and checking for them, or even by counting their faeces!
We had a nice walk and crossed tens of lines of pine processionary (Thaumetopoea pityocampa) caterpillars following each other down from the nest to the place where they would collectively bury for pupating. The last seasons have been extremely dry and many Aleppo pine (Pinus halepensis) trees have suffered the consequences and dried out, while pine processionaries seem to be extremely abundant this year.
While we had lunch at a restaurant in Espuña, the forest around gave sounds and views of chaffinches (Fringilla coelebs), robins (Erithacus rubecula), coal tits (Periparus ater), long-tailed tits (Aegithalos caudatus), chiffchaffs (Phylloscopus collybita) and short-toed treecreepers (Certhia brachydactyla). We even saw some jays (Garrulus glandarius) and red squirrels (Sciurus vulgaris) — I recently learned that Espuña squirrels form an endemic subspecies, Sciurus vulgaris hoffmanni.
A new field lecture has taken out this week. Again within Murcia, we set different activities and places to teach a variety of wildlife monitoring methods. First off we stopped around Lorca, one of the strongholds of the Greek tortoise (Testudo graeca) in southeastern Spain. The Greek tortoise is the target for several researchers in our department, and this has been my first time sharing some fieldwork with them.
It was somewhat cool, just around the temperature threshold for tortoise activity. We canvassed the slopes covered in esparto grass (Macrochloa tenacissima) and rosemary (Salvia rosmarinus) in different groups. We collectively found a good number of individuals and learned the basic features of population monitoring — main measures, sex, age, individual ID markings, and other interesting features such as aberrant shell scale patterns.
We were then transferred to a hostel in Sierra del Gigante, bordering with Almería in Andalusia. In the afternoon, we learned how to identify different skeletal remains of birds and mammals from this region using a reference collection with some impressive specimens. Students got to understand the importance of knowing bones by looking through the remains of pellets of barn owls (Tyto alba) and long-eared owls (Asio otus). Bone morphology can inform about the differences in resource exploitation in time and space even among the same species. Indeed, in some of the students’ pellets, we could tell the species and age of some preys thanks to the skeletal remains.
Later in the evening, we all hiked through the Aleppo pine forest up until a viewpoint. Red crossbills (Loxia curvirostra) were among the only birds singing before dusk and we all enjoyed good views of a singing male, learning about the unique ecology of this nomadic species, with an extreme bill adaptation to exploit pine cone seeds.
It got dark when we were still hiking, and we stopped and heard around us a couple of times. Two cooperative tawny owls (Strix aluco) started calling each other not too far away, and became the highlight for some of the students. The forest in Sierra del Gigante is greatly dominated by Aleppo pine, which provides good vegetation cover for this owl to forage but not to breed. Interestingly, tawny owls usually nest on rocky crevices in these forests, and indeed calls came from the cliffs nearby.
The following morning was all about birdwatching. First, we performed bird surveys in the pine forest while walking down the road from the hostel. Even if forests in southeastern Spain might not be the most dense, being familiar with bird calls and songs is fundamental to identify birds in forested areas. Aided by Merlin, field guide books and us teachers, the students got to point out different birds in the woods, many realizing how most of them remained unseen but were indeed present.
Red crossbills, short-toed treecreepers, coal tits and serins (Serinus serinus) called abundantly, even if we did not actually see any of these species throughout the walk (it was not the aim of the survey, anyway). We also detected crested tits (Lophophanes cristatus), long-tailed tits, rock buntings (Emberiza cia), greenfinches (Chloris chloris), goldfinches (Carduelis carduelis) along the way. A pair of ravens (Corvus corax) flew over, as so did several small groups of griffons (Gyps fulvus). The sharp eye of one of the students got a fast, buff raptor — a goshawk (Accipiter gentilis) flying fast over the forest. Great!
After bordering some marble quarries we got to the bottom of the road at a reservoir. Next to it, a viewpoint gives a great perspective to a singular cliff. Griffons are the only regular vulture species in the Murcia region, but became regionally extinct during their population drop some decades ago, and reappeared as breeders in the region by settling some nests exactly in this cliff. The griffon colony in Sierra del Gigante is thus relevant on a local context. For us, it also provided a great chance for students to get familiar with the use of telescopes and other optics to monitor the development of nests in a colony, far in the distance to prevent unnecessary disturbance.
Finally, we went on another short hike to retrieve some trail cameras set by part of the team some days before. These devices have vastly changed the way animal research is done by monitoring species that often remain unseen by other means. As a clear example, the species captured by these cameras were not among those we had seen during the lectures — an elusive stone marten (Martes foina) and two Iberian ibex (Capra pyrenaica).
Sierra del Gigante turned out to be an interesting place, and some colleagues explained how poorly monitored for birds the area is — sad it lies so far from home. Indeed, some of the rock walls seemed really suitable for certain rock-dwelling goodies. Besides several crag-martins (Ptyonoprogne rupestris), it was nice to find a good-sized colony of newcomer house-martins (Delichon urbicum) on the top of a small cave — the ancestral habit of a species most often seen breeding under roofs and bridges nowadays.
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