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| 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!
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| Rufous Hummingbirds (photo by Jannaca Chick) |
