Surrounding each aerodrome there is, or there should be, a volume of airspace that is intended to protect aircraft flying in the aerodrome's vicinity at low levels.  Although these are usually considered to be aircraft departing or approaching the airfield, it must be borne in mind that this is not necessarily the case.

The lowest level of this protective airspace varies in height according to orientation to the runways, and distance from the aerodrome. Close to the aerodrome it can be down to ground level, while further away it can be 150m above the airfield. 

Within the footprint of this airspace there is an area in which a development likely to attract birds will be seen as a hazard.  Although it is difficult to believe, birds can, and occasionally do, cause considerable damage to a fast moving aircraft.  Indeed, it is not unknown for a single bird to cause the destruction of an aircraft engine, or to puncture the aircraft's pressure hull, or to do other damage that would put the aircraft's safety at risk.

Bright lighting, tall cranes, electronically reflective materials can also present a hazard to the safety of aircraft. 

The aerodrome staff assessing a development proposal will seek to have all the risks these issues present addressed and minimised.