First, we need to change 1.476 minute to seconds
1.476 minutes = 1.476 x 60= 88.56 seconds
Let the number of times they flap there wings in 1.476 minute be X
69 times = 4 seconds
X = 88.56 seconds
cross-multiply
4X = 69(88.56)
4X= 6110.64
Divide both-side of the equation by 4
X = 1 527.66 ≈ 1 528 times