Worst shock I had with birds happened on an autumn evening approach to Glasgow.
Came out of cloud on the ILS over the river and saw what I thought was a bit of low stratus directly between me and the numbers.
At the last minute, realised it was geese, quite a few, and went around.
On a gentle walk from the hotel around the back of the airfield the next morning, spotted what had been the cause for concern.
Something approaching 200 greylag geese were having their breakfast in a field just to the side of the runway !
170 odd passengers should be grateful we weren’t more tired !! ……..and I learned about flying from that !