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
Three Little Birds chorus. The source of Marley's inspiration for the lyrics of "Three Little Birds" remains disputed. They are partly inspired by birds that Marley was fond of, that used to fly and sit next to his home. Tony Gilbert, a long time friend of Marley, was present at the time he was writing the song and elaborated, "Bob got inspired by a lot of things around him, he observed life. I remember the three little birds. They were pretty birds, canaries, who would come by the windowsill at Hope Road." However, three female singers from the reggae group I Threes who