Evidence presented by a University ornithologist has somewhat substantiated the Federal Aviation Agency's theory that a flock of starlings, sucked into the engine on take-off, caused the Eastern Airlines Electra to crash Tuesday night at Logan International Airport, killing 61 persons.

The FAA asked for a laboratory check of dead starlings on the runway, after Gen. Elwood Quesada, Federal Aviation Administrator, theorized that the plane hit a flock of birds on the runway.

Raymond A. Paynter, associate curator of birds at the Museum of Comparative Zoology, determined the next morning that the starlings were killed about the time the ill-fated plane crashed into Winthrop Bay. After examining remains of the birds, Paynter could ascertain that they died late in the afternoon, that they were hit by some powerful object, and that they were on the airport runway.

Paynter submitted his opinion after examination of certain tissue segments and of the birds' stomachs (which were full, indicating that death was at the end of the day). He called his method of determination "highly empirical."

On the basis of Paynter's findings, the FAA now assumes that the plane flew through a flock of starlings, some of which jammed the engine. The agency expects to find bits of birds in the engine when it is salvaged from the Bay.

Paynter had previously been advising the Fish and Wildlife Service on ways to combat the dangerous flocking of seagulls around the airport. He had expected to hear that gulls caused the crash, he said, because it was a flock of gulls, not starlings, which had previously proven bothersome at Logan and had prompted the Fish and Wildlife Service's action.

One Harvard biologist surmized that any birds caught in the engine would have been burned or thoroughly mangled beyond recognition.