Canal de Castilla Rey (Palencia), considered the beginning of the Northern Branch, Valladolid and Medina de Rioseco, lying at the end of the Southern Branch and Campos Branch respectively. The countryside crossed by the canal is of interest for its birdlife. In the Tierra de Campos there are two large Special Protection Areas ("La Nava-Campos Norte" and "La Nava-Campos Sur") which are notable for the birds such as great bustards ("Otis tarda") which live in the dryland farming areas (sometimes described as "steppes") which are typical of the region. The canal, on the other hand, provides habitats for wetland birds such as the
Xylota tarda Russia and the Caucasus then through Russia to Siberia and the Pacific coast (Kuril islands). Old woodland species running on the foliage of bushes and shrubs and on tree stumps and nearby bare ground. The larva has been found in sap runs at the base of the trunk of "Populus tremula" and in rotting wood of "Fagus". Xylota tarda Xylota tarda is a Palearctic species of hoverfly. External images For terms see Morphology of Diptera<br> Wing length 5·5-8·5 mm. Large red areas on black abdomen. Wing membrane not infuscated. Dorso-apical white bristle on metatarsus 1. Antero-dorsal pale hairs on the