The Iberian rabilargo.

Among the corvids of the Iberian Peninsula, most of them of a dark black color that in the past helped to evoke prejudices and unpleasant values attributed by the populace, there is one that stands out for its colorful livery. This is the case of the Iberian rabilargo (Cyanopica cooki), the smallest of the corvids that live in Spain.

The body of the white-haired whale is complemented by the contrast of its white throat and black capped head. However, more than this natural contrast, what attracts the most attention to the eye when observing this animal in the field are its blue colors. Well, the blue color of its primary feathers and its long tail gives it an unmistakable appearance.

Formerly, it was believed that the Rabilargos were a single one with a unique distribution made up of an Asian and an Iberian population separated by thousands of kilometers. At present, the advancement of scientific knowledge has demonstrated that gender Cyanopica is made up of two well differentiated species. The Asian Rabilargo (Cyanopica cyanus) and the Iberian rabilargo (Cyanopica cooki) that we are talking about. Genetic, morphological and biogeographic analyses concluded in the separation of these species, whose origin is hypothesized through an evolutionary process of speciation that we call allopatric speciation or vicariance and which consists of the fact of an original species whose populations are geographically separated and these develop separately without genetic flow between them, giving rise to new species. It is believed that the Pleistocene scenario of glacial and interglacial changes separated the whales and contributed to giving rise to these two species (Fok et al., 2002; Kryukov et al., 2004).

Surely any nature enthusiast who enjoys strolling through places inhabited by whale sharks will be familiar with the sound of this species. Since its plumage is unmistakable, the sounds it emits are also unmistakable: a diverse amalgam of squeaks, clicks and screams that serve as a complex communication system between individuals of the same species.

Bee-eaters are an extremely sociable species, which helps them survive in their environment. This social complexity is a feature to highlight in order to understand the natural history of this bird. If a rabilargo discovers a sufficient source of food, it will let its congeners know that very soon they will come to share the loot. When it comes to breeding, these animals find a solution in breeding in group territories where they concentrate their nests in a given environment. In the case of breeding, they usually have non-breeding relatives who help to obtain food and feed the chickens. Communal breeding and the defense of breeding areas by the whale community is a very important behavior for their success, given that many clutches are lost and not all chickens survive their first months due to the predation rate they suffer, these being food for a multitude of predatory vertebrate species (Villa 2000). In this regard, it should be considered that the Iberian whitefish forms part of the diet of different predators, both birds and mammals.

Figure 4 Photograph of Iberian rabilargo by Marco Ansón

Rabilargos, like most corvids, have an important and fundamental advantage: they are omnivorous. Rabilargos, such as magpies, show enormous trophic plasticity when it comes to exploiting food resources according to their availability in space and time. However, according to the studies carried out, the majority of the diet of these small corvids is composed of invertebrates, mainly arthropods (Consul & Álvarez, 1978; Pulido 1996). However, it is true that they consume vertebrates through access to carrion and the capture of other animals.

Unfortunately, the generalist adaptation of these corvids has given them bad press among some individuals, who, as a result of ignorance and ignorance, wrongly interpret that the whale whale kills the nests of other birds without leaving one. Totally removed from reality, the capacity of the whale shark to capture and consume small vertebrates is clearly true (Holyoak & Holyoak 2012), but it is well known that this is not representative of their diet and that it occurs as a form of resource exploitation in a situation of optimization. In the analysis of the diet of Iberian whales, a very small percentage of vertebrate presence has been found, corresponding to levels as low as less than 5%. Dietary studies also find the consumption of plant foods, with a predilection for fruits and seeds (Consul & Álvarez, 1978). However, during breeding, chickens are fed an almost completely animal-based diet, which coincides with the seasonal abundance and development phase of the chickens themselves (Canario et al., 2002).

Therefore, we should not stop marveling at this unique and endemic species such as the Iberian imperial eagle.

Figure 5 Photograph of Iberian rabilargo by Marco Ansón

References:

— Canario, F., Boieiro, M., Vicente, L. 2002. The Nestling Diet of the Iberian Azure-winged Magpie Cyanopica cyanus cooki in the south-east of Portugal. Ardeola, 49:283-286.

— Consul, C., & Álvarez, F. 1978. Rabilargo diet (Cyanopica cyanea). Doñana Acta Vertebrata, 5, 73-88.

— Fok, K.W., Wade, C.M., & Parkin, D.T. 2002. Inferring the phylogeny of disjunct populations of the azure—winged magpie Cyanopica cyanus from mitochondrial control region sequences. Proceedings of the Royal Society of London. Series B: Biological Sciences, 269, 1501, 1671-1679.

— Holyoak, D.T., Holyoak, G.A. 2012. Azure-winged Magpie killing and eating a fledged juvenile House Sparrow. British Birds, 105, 10, 628

— Kryukov, A., Iwasa, M. A., Kakizawa, R., Suzuki, H., Pinsker, W., & Haring, E. 2004. Synchronic east—west divergence in azure‐winged magpies (Cyanopica cyanus) and magpies (Pica pica). Journal of Zoological Systematics and Evolutionary Research, 42, 342-351

— Pulido, J.P. 1996. Annual evolution of the Rabilargo diet, Cyanopica Cyanus cooki Bonaparte 1850, in a grassy oak forest and an impact on the agricultural elements of the Municipality of Don Benito. Bachelor's Thesis. University of Extremadura. Badajoz

— Villa, A.J.R. 2000. Reproductive biology of the Rabilargo (Cyanopica cyanus). Parent-child relationships, Doctoral Thesis, University of Córdoba, 112 pp.