ML599140731

觀察細節

All over the campground. The BRBL were making short calls as they foraged on the ground as a group. The calls appeared to be contact calls to keep the group together. There were large groups of vocalizing TRBL and BRBL so this turned into an opportunity to differentiate their calls. Both were making short chunk calls while foraging. All these blackbird recordings included visual ID. Key differences: 1 - The BRBL call was shorter in duration, sounding “crisper”. The BRBL call was nearly always shorter than 0.05sec. The TRBL was usually longer than 0.05sec. 2 - The TRBL calls were more varied in note shape. The BRBL had one or two note shapes they were doing over and over. The TRBL was cycling through about 5 different calls. 3 - The BRBL note shape was most commonly a “rounded cap”, looking like an upside down u shape. It also made a few slanted calls shaped up / or down \ but those were less common. The TRBL had a larger variety of note shapes, including a triangular cap shape ^, a downward slant shape \, a flat note with a harsh squeak at the beginning, and others.