Not being a scientific writer, I enjoy some freedoms of opinion and at times cross over into fiction and fantasy. Usually, it's easy to tell the difference. I would like to seriously propose to birdwatchers that birds have a full array of emotions!
In his book The Expression of the Emotions in Man and Animals, Charles Darwin even dared to imagine a dog's conscious life. He was correct in that I have dreams, anger, love, jealousy, relief, curiosity, compassion and disappointment to a degree of intensity that is paralleled to humans.
I lead an intense emotional life and believe I am no different than the birds in this respect.
The Booby chick is born with jealousy to a degree that it kills its siblings, leaving only one chick per nest that gets all the food and attention.
Ornithologists classifying bird mating have defined a number of systems in which it would be in a bird's genetic interest not to allow its partner to mate with others. They speak in terms of "monopolizing", "defending", or "guarding" mates, not in terms of love and jealousy, but jealous behavior enforced with an exclusivity in mating which can certainly have genetic effects.
Birds seem to get angry; they certainly do commit aggressive acts against each other, fight for turf, and hurt and kill one another.
The bird books will say "brutal" or "savage" but the word anger does not appear.
Hate is most obviously displayed in parrots. Haven't you heard parrot owners make comments like, "He hates all men," or "It hates children," "redheads", or "dogs"?
It remains unknown whether these kinds of eccentric dislikes are found in the wild, but perhaps these parrots simply enjoy having enemies. This may promote flock solidarity, prevent interbreeding between species, strengthen the pair bond, or have some other valuable function.
Most psychological theorists have tried to list emotions that are universal. The lists range in number from 154 to 3. Theorists do not agree on which emotions are basic ones. I found it interesting that love never fails to appear on the list.
For Elbert to describe the birds of Ambergris Caye without including their emotions would be a disservice.
To understand birds, it's essential to understand how they feel. Knowing the emotions of birds is easy as knowing your own emotions; what would they feel can be answered with, what would you feel?
I hope this clears up the issue of Emotions in Birds for you, I have to go now, Elbert just pulled up in the boat and he doesn't like me using the typewriter.