Looks like over-preening/plucking/barbering (hard to say for sure-- could be a combination). I don't own an Amazon though, so in terms of whether they shed feathers when temperatures change, I don't know (nor do I know how much is typical in those cases).
Do you find a lot of feathers on the cage floor? Have you seen your bird preening a lot?
If they are just falling out, that would be a different story, but it looks like they are all missing in places where your bird could reach with his/her beak.
Stress, boredom, diet, environmental irritants, pain and/or hormones are common reasons for a bird to start plucking.
Here are some general things to consider:
If you haven't, make sure you get your bird checked by a CAV (certified avian vet) at least 1x per year (yearly CBCs---aka bloodwork= very important, as birds hide illness).
Make sure you are not using any scented products or chemical cleaners in your home (unless certified avian-safe). This means no bleach, windex, fabreeze, candles, carpet cleaners, air fresheners, etc etc. They have very sensitive respiratory systems and chemicals can also cause them to itch and pluck.
Things that trigger hormones and should be removed:
Prevent access to any dark spaces or shadowy areas (in and outside of the cage)- e.g., huts, tents, low-ledges, under clothing, under furniture, pillows, blankets, bedding, paper piles, drawers, low ledges, boxes, tubes etc.
Only cover the cage at bedtime and uncover in the morning (cover and uncover at roughly the same time each day).
Warm/mushy foods can also trigger hormones, so it is best to avoid these when possible hormonal issues are occurring.
Your bird needs 12 hours of uninterrupted sleep nightly in order to regulate mood, hormones and immune function.
Do not feed human food unless it is in extreme moderation and low in salt/sugar/preservatives. Aside from the risks to internal organs, things like salt and preservatives can cause skin to itch and preservatives in excess can impact behavior.
Make sure when you pet your bird you do not "cuddle" it---you want to pet only on the head and neck--- the rest is sexual and can lead to sexual frustration (plucking can be a sign of a frustrated bird). This rule stands all of the time--it is very important. Birds often crave inappropriate contact from us and indulging this desire can cause them to view us as mates---and that is a whole ball of wax that you don't want to deal with.
Make sure your bird is getting plenty out of cage time and that it is on a regular light/dark schedule (note: too much sunshine can cause hormonal behavior, but not enough can also be problematic).
Make sure you rotate toys in and out and that you give your bird time to acclimate to new ones before locking him/her in the cage with them.
Teach independence and praise your bird when it plays on its own---a bird who has to be with you at all times is going to be more prone to neurotic behaviors.
In terms of diet, seed should be limited---pelleted diets are generally recommended, along with fresh fruit and veg (not too much fruit due to the sugar content--it can lead to hyperactivity, obesity and diabetes in excess).
If you notice your bird plucking, try not to attend to it, as this can be seen as a reward (plucking=attention from the flock).
You can try lightly spritzing your bird with water (make sure there are no drafts nearby and that you never do this right before bed)---sometimes a daily spray down can reduce plucking behavior, but it isn't intended to be a punishment. If your bird doesn't like it, don't force the issue.