The bird problem on landfills is different from that of crops. Here the pest bird is different - generally Seagulls, and sometimes Crows. And the problem is not protecting a valuable crop, the problem is protecting the neighboring area from bird droppings.
Falcons and Hawks are flown during daylight hours on the days the landfill is open and uncovered. Landfills also benefit from the use of noisemakers such as "screamers", "whistlers" and caps. But the use of such noisemakers is dependent upon the proximity of neighbors.
Some landfills have a year-round bird abatement problem, for others it is seasonal and dependent upon migratory patterns. Migratory birds are protected by various international treaties and conventions, so it's important that any abatement be performed in a legal manner.