The phrase "a flock of two" is correct and usable in written English.
It can be used to describe a small group of two animals, typically birds, that are together.
Example: "As I walked through the park, I noticed a flock of two swans gliding gracefully across the pond."
Alternatives: "a pair of" or "a couple of".
The birds mated; she then had a flock of eighteen.
Then a real surprise: a flock of five goosanders, a scarce winter visitor, flying low overhead.
But last August, she spotted a flock of five of them, walking around her property.
A half-hour later, we spotted a flock of seven mallards flying from left to right in front of us.
Buzzards Gregarious in hunger, a flock of twenty turn circles like whorls of barbed wire, no spot below flown over uncanvassed.
In "Hen's Teeth" a flock of six young women in winged and feathered tunics performs what might be a new-look idea of a dance for a 19th-century corps de ballet.
The Jamaica Bay white pelican is the first one sighted within the city limits, though since 1885 there have been seven sightings of white pelicans on L.I., the largest gathering being on Shelter Island on Oct. 12, 1926, when a flock of six flew in.
A flock of fifty adult American white ibis were killed in a fire in the Everglades.
Patient A lived on a farm with two cows, two horses and a dog, while Patient B lived on a farm with a flock of ten sheeps.
A flock of sheep, two cows, four donkeys, a cat named Mother, chickens, a rooster and four dogs — these are the central characters of Jon Katz's "Dog Days," a chronicle of recent doings on the farm where he lives in upstate New York.
SOUTH ORANGE, N.J. — Three blocks up from the historic brick train station — past the Grid Iron Waffle Shop, the grocer and a flock of quaint two- and three-story buildings — Alex Torpey was working at his desk one recent afternoon in South Orange's Village Hall.
