Erratic and increasing temperatures, linked to climate change, may also be encouraging some migratory birds to stay put. Of additional concern, is the impact that electronics may have in disrupting the internal magnetic compass of migratory birds, as recently reported in Nature.
Even when robins do migrate, new studies show that robins, and other migratory bird species, are returning much earlier in the spring – as much as 30 days earlier. Will natural food sources be available to these birds during a tough winter, or when they arrive prematurely in the spring? To some extent, that may depend upon you, and what you have planted in your yard.
In the spring and summer, robins primarily eat invertebrates, particularly relishing earthworms and caterpillars. When the cold weather arrives and invertebrates are less available, or completely absent, overwintering robins shift their diet to fruit. While some robins have been spotted consuming an occasional hulled sunflower seed, persistent fruits are their mainstay in winter.
There is not much you can do to coax insects out of hiding in winter, but you can offer overwintering robins dehydrated mealworms for a protein boost. However, this is not a substitute for the fruit that they rely upon to get through winter. By planting regional native plants with persistent fruit, you can offer hungry robins, and other fruit-eaters, a welcome meal.
The following list offers a number of options, but make sure to select plants that are appropriate to your site (sun/shade; wet/dry, formal/naturalistic, etc.).
Native Plants With Persistent Berries
- Ilex verticillata (Winterberry)
- Ilex glabra (Inkberry)
- Ilex opaca (American Holly)
- Juniperus communis (Common Juniper)
- Juniperus virginiana (Eastern Redcedar)
- Morella pensylvanica (Northern Bayberry)
- Parthenocissus quinquefolia (Virginia Creeper)
- Photinia floribunda (Purple Chokeberry)
- Photinia melanocarpa (Black Chokeberry)
- Rhus glabra (Smooth Sumac)
- Rhus typhina (Staghorn Sumac)
- Rosa carolina (Carolina Rose)
- Rosa virginiana (Virginia Rose)
- Viburnum lentago (Nannyberry)
- Viburnum nudum
- Viburnum prunifolium (Blackhaw Viburnum)
- Viburnum trilobum (American Cranberry Bush)
If resources are few, some of these persistent fruits may not persist for very long! The palatability of some fruits depends on the freeze-thaw cycles of winter that help to concentrate sugars in the fruits. If you have ever enjoyed a glass of ice wine or a sweet Sauternes, you will have tasted the results of this process.
To avoid a shortage of resources, plant a variety of native plants with persistent fruit. But don’t stop there. Not all overwintering birds eat or favor fruits. Stay tuned for the next article offering more tips on helping overwintering birds.
Kim Eierman, a resident of Bronxville, is an environmental horticulturist and Founder of EcoBeneficial ! When she is not speaking, writing, or consulting about ecological landscapes, she teaches at the New York Botanical Garden, Brooklyn Botanic Garden, The Native Plant Center and Rutgers Home Gardeners School.
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