Anna's Hummingbirds and Feeders

Photo by Ann Nightingale

With the cold weather hitting Vancouver Island, we’ve received a lot of questions about feeding hummingbirds. We are fortunate to have Anna’s Hummingbirds on the island all year round, so here are some tips for all seasons:

Why do we recommend 1 cup sugar to 4 cups water as the “proper” formula for hummingbird food?

There are a lot of web sites that might tell you differently, so we have decided to explain in detail why we make this recommendation.

Dehydration

It may seem strange to suggest that drinking can cause dehydration, but higher sugar concentrations can cause hummingbirds to consume less fluids. Water shortages occur both when temperatures are high and when they are below freezing.

• In captivity, birds will dehydrate if they are using sugar water concentrations higher that 1:4. In fact, they use 1:6 in rehabilitation conditions.
• In the wild, birds can tolerate some slightly higher concentrations as long as they have a dietary source of water. Birds drinking at a concentrated sugar solution will often drink at fountains to reduce the sugar content.
• Water availability can become a problem during times of freezing, so while it is particularly important to keep your feeders unfrozen, we recommend a maximum concentration of 1:3.

If there is a chance of freezing, why do you recommend increasing the concentration to 1:3?

Truly, a 1:4 concentration is best and if you can rig up something like lights or a heating mat to keep the nectar fluid, then stay with that concentration. However, if you are unable to stop your feeder freezing, a slightly higher sugar concentration does help reduce the chance of freezing. This increase in concentration is not ideal, it is a trade-off - maintaining a liquid food supply while hoping that the birds can access some source of dietary water.

It is important to avoid the feeder freezing as sugar is not present in ice, so the remaining syrup has a huge concentration relative to the unfrozen nectar. This would cause more problems for the birds, as they would be consuming a high concentration of sugar with no water to offset the negative effects.

If it is bad for them, why do they like higher concentrations of sugar?

Wouldn’t you like an ice-cream sundae at every meal? No – really, the reason is that higher concentrations are not available in nature, so there has been no evolutionary selection of individuals that can discriminate against high sugar concentrations. This means that until we came along, it wasn’t a problem that hummingbirds had to deal with. Plants that specialize in hummingbirds do not provide more than 30% sugar and most are around 20%.

Why do these birds need so much water?

In summer, it is easy to see why they might need water for evaporative cooling, but there are also constraints on uptake when a high sugar concentration is in the gut. This is why the rehabilitators see the effects of dehydration even at 1:4.

Are there any other reasons why high sugar concentrations could be a problem?

Well, yes. Birds accessing high sugar syrups will often have preening problems. You can imagine how difficult it is to get something super sticky off of feathers. Another problem is that higher sugar concentrations attract more wasps, which can end up interfering with the bird’s ability to access the feeder.

Is there anything else I should know about feeders?

Yes, and the answers could probably fill a small book. However, the most important thing is to remember to keep your feeders meticulously clean. No harsh cleaners, though. If it’s not clean enough for you to drink out of it, your hummingbirds shouldn’t have to, either!

For more information, visit rpbo.org (Click on “Learn more”.)

Rufous Hummingbirds (photo by Jannaca Chick)