Altered Birds

The altered birds would firstly see their wing span increase in length, allowing them to fly faster and for longer periods of time without break.
Their beaks also increase in length, becoming very narrow at the tip. This allows the birds to more effectively consume scraps of meat on bones and insects/ grubs in harder to access areas.
They possess larger and sharper talons, giving them the ability to dig into different objects and sometimes creatures. These larger talons allows them to also grab and carry larger quantities of food (they can also pick up larger rodents and such).

Altered Bird's Behaviour

All these bird species become more scavenger like, which allows them to utilise their longer beaks in order to ensure they consume all scraps of meat on carcasses.
These birds rarely attack living creatures, due to them not being able to inflict fatal damage to them. They have been seen to attack healthy living creatures, although this is rare and when the creature is by itself and the altered birds are in flocks of larger numbers.
The altered birds also become extremely opportunist, and as stated previously, strategically deciding who/ what to attack and when to attack them. These affected birds are usually seen feeding upon already killed animals, or attacking animals that appear fatally wounded (close to death).