A particularly rare visitor popped in to visit the fish ponds of Kibbutz Maayan Tzvi near Zichron Yaakov this week, when a phosphorescent yellow "mixed" Nahliali (hybrid) bird, apparently created from a hybrid between lemon and yellow streamers, two organisms from different genetic populations.
The special and mysterious Nahlali was discovered in the same area last fall by birder Zur Magen, where he spent the winter, and it returned to the same site this year as well. Shahar Hezekiah, a one-year service volunteer from the Hof HaCarmel Field School of the Society for the Protection of Nature in Israel, documented him bouncing between the water reservoirs and the reeds. According to Dr. Yoav Perlman, director of the Birdwatching Center at the Society for the Protection of Nature in Israel, he is expected to spend the current winter in pools as well: "Only genetic testing can verify this hypothesis, but the external appearance of this individual is similar to documented cases from other parts of the world of hybrids between yellow streamers and lemony streamers. The sounds he makes sound like the voices of Nahlieli Limoni, which are completely different from the voices of the yellow Nahlili."
Surprising guest. Phosphorescent yellow streams in the area of Maayan Tzvi, photo: Adam Rosenfeld - Society for the Protection of Nature in Israel
Unique look. Phosphorescent yellow Nahliali, photo: Ido Ben Yitzhak
The Society for the Protection of Nature in Israel added that different species of animals usually do not mix, since they retain the genetic "identity" of the species. "Reproductive isolation, that is, the inability to produce common offspring, is one of the accepted ways in science to distinguish between different species," Dr. Perlman concluded. "However, in nature not everything is black and white, and there are many cases in which the 'boundaries' between species, genetic and morphological (external form), are blurred. Species that are genetically close to each other, such as species that separated during evolution relatively recently, can mix if there is contact between the populations of the two species, that is, when both species incubate in the same area."
He added: "It is likely that the parents of the Nahlili from the Deer Spring were lemon streamers and yellow streamers, two species that meet in large nesting areas, from Eastern Europe to Central Asia."
Unexpected mixing. Nahlieli Limoni, Photo: Yoav Perlman - Society for the Protection of Nature in Israel
Nahlieli Yellow, Photo: Yoav Perlman - Society for the Protection of Nature in Israel
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