Yes, hummingbirds eat aphids but I would still knock them off my citrus. Aphids can multiply rapidly and the HBs aren't a primary predator.

I would agree with Rhizo; if you want to feed the hummers get a feeder. I would also check around your citrus for ants; when you have aphids, you almost certainly have ants. If you control the ants, you won't have aphids.

I have to disagree with that statement, John. Aphids are perfectly capable and willing to to set up housekeeping without a single ant.

Aphids don't NEED ants, but some are equipped to establish a mutualistic relationship with them if they show up. Also, ants don't need aphids, but some species have evolved with behaviors that use aphids. Of course, once a scouting party of ants has discovered some fat aphids, they'll send a memo to all of rest of the colony.

Getting rid of ants is not the key to aphid control. Getting rid of the aphids is the key to aphid control. Nika's citrus could end up with a bad cifrus aphid problem without any ant influence whatsoever.

Now, it IS good policy to inspect a plant that seems to have a lot of ant traffic because that MAY be a sign that piercing/sucking insects are present. Remember, too, that some ants are nectar feeders, after the flowers and not insects. Citrus flowers can be highly attractive to ants.

We actually don't have any ants around the citrus, but I did knock down the aphids. Nasty little suckers!!!

Rhizo,
We have had this discussion before. I am aware that aphids and ants can exist independently; and I have seen aphids some times on my roses, when I did not find any ants...doesn't mean they weren't there, as in nocturnal... only that I didn't find them. I think citrus is a different issue, as neither I nor any of my citrus gurus or commercial grower acquaintances that I have asked has EVER seen aphids on citrus without the presence of ants. I used to have aphid problems in my first Meyer projects, until I learned this; since then I control the ants and I NEVER have aphids.
When I visit my associate growers and see aphid damage, I ALWAYS find ants; and when they control the ants, no more aphids. Maybe it is a citrus thing, or maybe it is only citrus aphid in particular; but some 20 odd years of learning and suffering and finally getting it right means I trust more what I have seen than what some common wisdom might tell me.

As a follow up, after I read through these responses I rechecked the tree. Sure enough, there were ants starting to crawl towards the aphids. I wound up removing the limb with the infesation yesterday afternoon. Rechecked today and didn't see evidence of either, but will continue to be vigilant!