ML646768799

觀察細節

Gnatcatcher calls coming from the field. All of these recordings are passive recordings (I was not there while recording). The gnatcatcher vocalizations were all between 7:08 AM and 7:21 AM. Sunrise was 6:45 AM. CAGN vocalizations typically have an arched up/down shape (that looks like a hill) for most or all notes. It’s reasonably symmetrical—slope up, slope down. In this recording the vocalizations match that shape consistently for 2+ minutes. Comparable CAGN recordings: https://macaulaylibrary.org/asset/644455966 https://macaulaylibrary.org/asset/629847610 BGGN vocalizations usually include more variability. They often do a call with a high peak right at the beginning, followed by a downward slope. That obvious BGGN call is absent here. They also throw in some really short notes, and their calls often seem busier and more active. In this case, that variability and business is absent. To me, the BGGN call is also a bit more “nasal” in tone. Reference BGGN calls: https://macaulaylibrary.org/asset/320899651 https://macaulaylibrary.org/asset/611385734 So in short…. This recording sounds more like a CAGN than a BGGN to me. CAGN is not expected at this location. As far as I know, CAGN has not been documented here, while BGGN gets reported regularly. Despite that, I wouldn’t be shocked if CAGN was here. There’s a certain amount of turnover to our birdlist depending on the varying states of the field vegetation and the state of the various ill-advised construction projects. So species come and go. And at the moment, the field is somewhat overgrown and shrubby, which has attracted some species that have otherwise been absent in the past (like the marsh wren). I just wouldn’t be shocked if the current field was attractive to CAGN.