Light Grey Sphere not moving then shots off no sound big

Every night I go into my garden with the dogs .
This night was very odd for many reasons .
Reason 1
It was just before 8.30 pm I had my watch on looked at time . What was strange all the Birds in the Surrounding area were making strange noises which I noticed straight away . I've never heard that before like that .
So I look up from Left To Right
See Areoplanes 2 infant crossing paths everything seemed normal in the Sky above but then way lower to my Left and I do mean way lower A Big Grey Spere light Grey in Color not moving just
There the birds were still making this Strange sound like panic it sounded like .
About 15 Seconds this Light Grey Sphere shots off In A Perfect Straight line not up or Down Just a Perfect Straight
Line . I'll be very honest with you I have never seen something move as fast ever like that before .
I'm still in shock .
As soon as it left the birds stop making that panic noise .
This Sphere Light Grey to me was trying to hide and not to been seen that was my 1st feeling about it I was kinda like a camouflage.
No sound was Big and super fast .
From Left Low Level Not Moving To Moving Straight Fast to the Right all lasted about 24 Seconds .