I went for a walk and there were quite a few migrant Chiffchaffs calling. The image is cropped.
OM-1 OM 150-400mm F4.5 TC
Focal Length (35 mm conversion) : 1000.0mm
Exposure mode : Manual exposure
ISO : 640
Exposure compensation : 0.0 EV
Shutter : 1/1600 sec
ACR/PSCC