On November 2, 2009, about 0850 mountain standard time, a McDonnell Douglas MD-90-30, N909DA, was substantially damaged following an in-flight collision with birds during climb to cruise flight 25 miles northeast of the Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona. The airplane was registered to and operated by Delta Airlines Inc., Atlanta, Georgia, under the provisions of Title 14 Code of Federal Regulations Part 121 as flight 1232. The airline transport rated captain and first officer, three cabin attendants, and 65 passengers were not injured. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the scheduled passenger flight. The cross-country flight originated from PHX at 0841 with an intended destination of Salt Lake City, Utah.

The captain reported that while climbing through about 12,000 feet, he heard a large bang with a "pop" in the pressurization. Subsequently, the captain noticed that the noise level was very loud within the cockpit. After a brief discussion with the first officer, the flight crew "decided it was a bird strike." The first officer reported that prior to the loud bang; he noticed "several black dots directly ahead of me." The flight crew declared an emergency and returned to PHX. The flight landed uneventfully about 10 minutes later.

Examination of the airplane by a Federal Aviation Administration inspector revealed an approximate 18 inch by 21 inch tear in fuselage skin located aft of the right side flight deck eyebrow window and structural damage to the upper portion of the fuselage. Bird residue and feathers were observed near the torn area of fuselage skin. Additional damage and bird residue was noted on the lower right side of fuselage.

The Smithsonian National Museum of Natural History Feather Identification Laboratory performed DNS analysis, microscopic examination, and whole feather comparisons with museum study skins on the recovered residue and feathers. The analysis identified the residue and feathers as the remains of a Western Grebe (Aechmophorus occidentalis). The weight range for the species complex is recorded from 906 to 1429 grams, with an average weight of 3.3 pounds.