Buteo borealis calurus

body mass

• Bergtold 1917: 64 oz (single measurement)
• Bergtold 1917: 48 oz (single measurement)
• Bergtold 1917: 39.5 oz (single measurement)

body temperature

• Bergtold 1917: 106.2 degrees fahrenheit (single measurement)

egg mass

• Bergtold 1917: 2.1 oz (single measurement)

prenatal development duration

• Bergtold 1917: 28 days (single measurement)
• Bergtold 1917: 28 days (single measurement)