Sunday, September 27, 2020

Why Natives Matter: Birds

Last week I wrote about how using Georgia’s native plants in our landscaping supports our native insects better than using non-native plants. In this post, I’d like to talk about why using native plants matters to our native birds.

The first thing to understand is what birds eat, both as an adult and as a nestling. The 3 main categories for adult birds are frugivores (fruits), granivores (seeds), and insectivores (bugs) like the hooded warbler at left, plus omnivores (a bit of everything) and nectivores (nectar-eating birds such as hummingbirds). The major food for nestlings is far and away insects (96% of birds eat insects when in the nest).

How do native plants help those different types of birds better than non-native plants? 

Insectivores – This category, which represents the vast majority of birds when you factor nestlings into the equation, benefits from the relationship of insects to native plants (what I talked about last week). Herbivorous insects (those who eat leaves and other parts of plants) have evolved with their plant partners to the point where some won’t eat any other plant. If you want insects to feed your birds and their babies, you should plant a variety of native plants and especially the keystone plants (a termed coined by Doug Tallamy to represent the plants that provide the most significant support to insects, see page 139 of his book, Nature’s Best Hope).

Photo by Romin Dawson

Granivores – This category of birds eats seeds primarily and includes one species of bird, the American goldfinch, who even feeds seeds to its young (in case you wondered who was in the 4% of nestlings not eating insects). While a lot of people do supplement these birds with purchased seeds, supporting them with plants is beneficial (especially when you run out of seed during a pandemic and don’t want to go to the store!).

A goldfinch eats thistle seeds (as seen through the deck slats)

– This category of bird consumes a lot of fleshy fruits but will occasionally eat insects or seeds depending on availability (still not enough to be considered an omnivore). These birds greatly benefited from the push to plant berry plants some years ago, sometimes to the detriment of the environment as well-meaning folks planted non-native plants that became invasive in some areas (think privet, autumn olive, mahonia, and nandina). Scientific analysis shows us that native fruiting plants provide more nutritious fruits than the non-native plants. This article from Audubon highlights several studies, including this one.

Left to right: Spicebush fruits, Beautyberry fruits, and American holly fruits are all very popular

So if you want to support birds as much as possible, plan to use more native plants. Check out my earlier blogs for tips:

Natural Bird Food

This is the final installment in my 3-part series on Why Natives Matter. If you missed the others, you can read the first one here: Sense of Place and the second one is here: Bees, Butterflies, and Bugs.

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