Nyjer seed, also known as thistle seed, is a popular type of bird seed that is commonly used to feed wild birds such as finches and siskins. However, some people have concerns that nyjer seed may also attract unwanted rodents to their yards. In this article, we’ll explore the evidence on both sides of this debate and provide tips on how to use nyjer seed responsibly.
What is nyjer seed?
Nyjer seed comes from the Eurasian plant Guizotia abyssinica, which is part of the sunflower family. It is also referred to as niger seed or thistle seed. The tiny, black seeds are rich in oils and nutrients that wild birds relish.
In particular, nyjer seed attracts finicky feeder birds that tend to avoid other blends, including:
- Goldfinches
- Pine siskins
- House finches
- Purple finches
- Redpolls
Unlike millet and other larger seeds, nyjer seed flows freely through tube feeders to allow easy access for small songbirds. Bird watchers favor nyjer seed because it brings in desirable and colorful visitors.
Do rats, mice, and squirrels eat nyjer seed?
The main concern with nyjer seed is that its small size makes it accessible to rodents as well as birds. Rats, mice, chipmunks, and squirrels are all able to eat at nyjer seed feeders along with songbirds.
However, the appeal of nyjer seed to rodents depends on several factors:
- Availability of other food sources – Rodents are opportunistic feeders and will take advantage of easily accessible food. If nyjer is their only option, they will consume it. But they likely prefer more substantial food items when available.
- Population density – Areas with high rodent populations put nyjer feeders at greater risk of nuisance activity. Rats and mice have to eat a lot each day to sustain themselves and will take advantage of any readily available food.
- Type of feeder – Rodents are deterred by feeders with weight-sensitive perches, small access ports, and smooth poles. Nyjer feeders with good protections can limit access.
- Yard maintenance – Keeping the area around feeders clean and free of debris reduces appeal to rodents looking for food and shelter.
While rodents will eat nyjer if given the chance, the seed alone is unlikely to be a major attractant. Other factors related to the local environment play a larger role in determining rodent interest.
Evidence that nyjer seed attracts rodents
There are some documented accounts of nyjer seed attracting unwanted rodent visitors:
- Mice and squirrels have been observed climbing poles to access nyjer feeders or knocking them down.
- Rats are able to chew through plastic and wood feeders to reach nyjer seed inside.
- Spilled nyjer seed on the ground can attract rodents to the area.
- Gnaw marks and small holes chewed in feeders provide evidence of rodent activity.
In addition, some observational studies have indicated higher rodent populations in areas using nyjer seed. A survey published in Wildlife Society Bulletin in 2002 found urban properties using nyjer seed had 5 times more squirrels than properties without feeders. And a study in The Condor: Ornithological Applications in 2018 observed increased overwinter mouse survival related to supplemental feeding, including nyjer seed.
So there is some evidence nyjer seed contributes to rodent food sources in localized areas. However, the study authors acknowledge population density, sanitation, and habitat factors also play a role.
Tips for using nyjer responsibly
For those who want to enjoy nyjer seed as a way to attract wild birds but limit rodent issues, here are some tips:
Use weight-sensitive or small-ported feeders
Specialized “squirrel-proof” feeders with weight-sensitive perches or small access ports can allow small birds in while restricting entry to heavier rodents. Pole baffles also deter climbing squirrels and rats.
Provide separate large seed feeders
Putting out sunflower seeds, millet, cracked corn, or other large seeds that rodents prefer can divert them from the nyjer supply. Place these offerings away from tube feeders.
Use feeder trays
Trays secured firmly to the ground below feeder ports can catch dropped nyjer seed so it doesn’t accumulate at ground level within reach of rodents.
Clean up spillage
Be diligent about sweeping up any nyjer seeds or hulls below feeders to avoid attracting rodents to the area. Consider placing feeders over patios or gravel beds to make cleaning easier.
Remove feeders at night
You can take feeders down at dusk when birds stop feeding, then put them back out in the morning. This removes a nighttime food source that rodents may rely on.
Use feeders selectively by season
Because nyjer seed attracts winter finches, you may wish to remove nyjer feeders during warmer months when these birds migrate away and rodent populations are more active. Save nyjer for the cold weather when favored birds are present.
Eliminate nearby rodent habitat
Clearing brush and debris around the yard removes shelter and nesting sites that may encourage rodents. Trim vegetation back from feeders so rats have fewer hiding spots.
Set up owl or hawk decoys
Life-size plastic decoys of predatory birds can frighten rodents away from feeders. But they need to be moved occasionally so rodents don’t catch on to the fake threat.
Use repellents
Spreading capsaicin-based squirrel repellent around nyjer feeder poles and the ground below can discourage nibbling. But re-application is required after rain or snow.
Consider not using nyjer
If rodent problems persist despite all efforts, switching to safflower or sunflower seeds may be necessary. While less ideal for finches, these larger seeds are more rodent-proof.
Conclusion
Nyjer seed alone does not necessarily attract rodents in all cases. But under the right conditions, rats, mice, chipmunks, and squirrels will take advantage of easily accessible nyjer at feeders meant for birds. The key is making feeders rodent-unfriendly through protected designs, strategic placement, and yard maintenance. Responsible nyjer feeding greatly reduces risks of attracting unwelcome visitors.