How Fireworks Harm Nonhuman Animals
Fireworks and other explosive materials, whose reactions can produce sparks, flames, and fumes, cause various harms to nonhuman animals. These often affect animals who are human companions, and whose reactions we can easily see. They also harm the other animals who are around us, both in urban environments and outside them, as well as those who are on farms or confined in other spaces.

It has been pointed out that the reaction of dogs to the sound of fireworks is similar to post-traumatic stress in human animals. However, this effect could be much more harmful in dogs, because they do not have the ability to rationalize their anxiety, or the possibility of an immediate cognitive response that allows them to respond to their fear. Horses also act quite similarly to dogs and cats, showing signs of stress and fear, and trying to flee or escape. The noise of firecrackers can cause birds tachycardia and even death by fright. The high degree of stress birds experience is indicated by the fact that birds may temporarily or permanently abandon the places where they are. Many birds, and squirrels alike, who flee from their nests due to the sounds do not know how to return to their nests once the noise ends, which leaves many of their young helpless to die. 

In addition, firecrackers are poisonous, and their explosion releases harmful particles such as fine dust (PM10) that is toxic to inhale. It can worsen existing diseases and cause others. Therefore, fireworks represent a danger both to animals who live in areas where they explode, or in relatively distant locations when the wind transports the particles. There is also a risk of ingestion of the residue of fireworks and firecrackers. The proximity of the animals to the areas where the firecrackers are made often causes burns and damage to the eyes.

There is a growing acceptance of alternatives to fireworks, such as laser light shows. One notable case is in the city of Collechio (Italy), one of the first to program silent fireworks, with the message that it is possible to enjoy fireworks without causing panic among the nonhuman inhabitants of the municipality. However, there is the possibility that this type of show may affect birds negatively.

~ Animal-Ethics.org