. Der Ornithologische Beobachter. Ornithology; Birds. Junge Zwergrohrdommeln (Ardetta minuta). Nest am Bielersee. Beilage zum „Ornithologischen Beobachter^', Heft o, 1921/2: 0 fi, C. Z6INQENS0«, flAsa. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Ala, société suisse pour l'étude des oiseaux et leur protection. [Bern? : Ala, Schweizerische Gesellschaft für Vogelkunde und Vogelschutz] - Stock Image