FO Kite,
Certification takes care of bird strike, but in the GODs, I was always amused that the Imperial Standards Bird only flew to 8,000 ft, but the FAA Bald Eagle flew to 10,000 --- which hardly covers Condors over the Andes, where birdstrikes have been recorded at 28,000. I personally have had a bird strike --- at night --- at 17,000 over Bangkok ---- doing about 340kt at the time, hell of a bang, but no damage to the aircraft.
An aircraft AFM will detail any operational limits to ensure bird strike protection, but in more recent times, many aircraft (eg: B747) do not have any birdstrike limitation speeds.
Re. 250 kt/10,000' speed limits, some are statutory (eg:US) and ATC cannot give "dispensations", it is up to the PIC to determine that a minimum safe speed is greater than 250kt. From memory, FAR 91.117.
In some countries (eg: Australia) it is a bit more complicated, it is a statutory limit in D, E and G airspace, but up to ATC in C.
Tootle pip!!