Grackles and blackbirds: a seasonal problem with a seasonal fix

The short answer

• Grackle and blackbird pressure is a spring migration event in most of the continent. It peaks between late February and May, fades through June, and returns in a smaller late-summer wave of juveniles.
• Safflower is the single most effective change. Common Grackles rate it as not a feeder food at all, while cardinals rate it as a top-tier favorite, so the seed does the sorting for you.
• Switch to safflower over three weeks by blending, not overnight. A hard switch usually looks like a failure in week one and gets abandoned.
• Weight-activated and caged feeders exclude a 115 g grackle reliably, but a 1.5 in cage mesh also excludes your 45 g cardinal. Pick the mechanism that matches the birds you want to keep.
• Common Grackles and Red-winged Blackbirds are native North American birds, protected, and in long-term decline. The goal is to move them off your feeder, not to harm them.

The complaint is always the same and it is always the same six weeks. A feeder that lasted a week in January is empty by Wednesday. There are twenty large glossy birds on the ground, six more on the tray, and the chickadees have vanished. Nothing about your setup changed. What changed is that a very large migrating flock has moved through your area.

That is the first useful thing to know, because it changes what you should do. This is not a permanent invasion that needs a permanent war. It is a pulse, and most of the effort should go into making your station boring for six weeks rather than rebuilding it from scratch.

The calendar, and why it matters#

Common Grackles winter in large mixed roosts, mostly in the southern and central states, and move north in a compressed window. In most of the East and Midwest the first flocks show up somewhere between late February and mid March, numbers peak in April, and by mid June the birds have dispersed into breeding territories and your feeder goes quiet again. Red-winged Blackbirds run slightly earlier, with males arriving first.

Then there is a second, smaller wave. Once young birds fledge in July and August, family groups band together and start moving, and a yard that was calm in June gets a fortnight of juveniles in August. It is shorter and less intense than the spring pulse, and the same measures cover it.

Safflower, and the honest version of how it goes#

Safflower is a small white seed with a hard shell and a bitter coating. The preference split around it is unusually clean, and it is the reason this page exists.

Top top-tier favorite Yes eats readily Some takes occasionally Rare rarely No not a feeder food

Read the safflower column. Common Grackles score zero, meaning it is not a feeder food for them at all. Red-winged Blackbirds barely register on it. Cardinals score it as a top-tier favorite, the same rating they give black oil sunflower. Chickadees, titmice and house finches all eat it readily. Mourning doves take it. That is the whole trick: the seed sorts the birds so the feeder does not have to.

The part nobody tells you is the first fortnight.

The three-week transition that actually works#

A hard overnight switch to pure safflower usually gets abandoned on day four, because the cardinals have not worked out that it is food yet and the yard looks dead. Blend instead:

Two rules make or break it. Do not run a second feeder with the old seed anywhere in the yard during the transition, because the flock simply moves across and never learns. And accept that weeks two and three produce more ground mess than usual as birds sort through the blend, so sweep every evening. If you want the fuller comparison of what each seed buys you, see safflower versus sunflower and the safflower seed page.

Removing the food they can actually reach#

Grackles and blackbirds are ground and tray birds. Both score the maximum on ground feeding in our data, and both list platform, ground and hopper as the feeders they use. Nothing in that list is a tube.

So before you buy anything:

1. Stop all ground feeding for the duration. No scatter feeding, no seed on the patio, no corn on a stump. Cracked corn is the single strongest grackle magnet on the food table, and it is also the cheapest thing in the shop, which is why so many yards have it out.
2. Take the tray off the tube. A wrap-around tray is the best upgrade a tube feeder can have for eleven months of the year and a liability in April. Remove it for the pulse and put it back in June.
3. Retire the open platform. A platform feeder is a grackle table. If you use one for cardinals and jays, run it as a short lunchtime service with a small quantity rather than leaving it stocked.
4. Sweep the ground every evening. Twenty minutes of raking under the feeder does more than any gadget, and it is also the thing that stops the second problem, which is rats and mice.
5. Switch hearts to in-shell. This one is small but real: grackles rate sunflower hearts above in-shell black oil, because there is no shell to deal with. Going back to in-shell seed adds a handling cost that matters more to a big bird in a hurry than to a chickadee.

Feeders that a 115 g bird cannot use#

Once the food is right, geometry does the rest. There are three mechanisms and they are not interchangeable.

The weight number is the one worth thinking about. A Common Grackle runs about 115 g and a Northern Cardinal about 45 g, so there is a wide gap to set a trigger in. A mechanism that closes somewhere around 70 g keeps every cardinal and drops every grackle, which is exactly the band most adjustable weight-activated designs cover. A cage cannot make that distinction, because a cardinal is physically too broad for a 1.5 in mesh. If your yard is a cardinal yard, that single fact decides the purchase for you, and it is worked through in more detail in caged versus weight-activated feeders.

Nyjer, and the finch station that survives all of this#

If you feed goldfinches, you already own the one feeder in the yard grackles will never touch. Nyjer scores zero for both Common Grackles and Red-winged Blackbirds, the ports on a nyjer feeder are slits too narrow to work for a heavy bill, and there is nowhere for a big bird to stand. Through the worst of the April pulse, the nyjer feeder is often the only station still running normally.

That is worth remembering when the yard feels empty in week two of the transition. You have not lost the birds, you have narrowed the menu for a few weeks.

Common Grackles are not the enemy#

This is the part that gets left out of most advice.

The Common Grackle is a native North American bird. It has been part of this continent's landscape far longer than the feeders it now raids, and it has been in long-term population decline for decades, which is not the profile of a species that needs to be fought. It is not in the same category as the European Starling or the House Sparrow, both of which are introduced and unprotected in the United States. Red-winged Blackbirds are likewise native and federally protected.

In practice that means the acceptable toolkit is: change the food, change the feeder, remove the ground supply, and wait out the season. Trapping, poisoning and destroying nests are not on the list, and in the United States and Canada the protected status of these species means they are not legally available to you either. If you believe you have an exceptional situation, your state or provincial wildlife agency is the right place to ask, not a forum.

Putting the season back together#

Come mid June, most of this can be undone. Put the tray back on the tube, restart the platform if you use one, and decide whether to stay on safflower. Plenty of people never go back, because the station stays calmer and the squirrels stay off it. Plenty of others switch back to black oil sunflower for the broader appeal and simply repeat the routine each March, which is a perfectly reasonable way to run a yard.

Either way, put it in the calendar. Grackle season is predictable, and a problem you see coming in February is a much smaller problem than one that ambushes you in April. The spring feeding guide covers the rest of what changes in the same weeks, and the bird feeding calendar puts it in order.

Frequently asked questions#

What seed do grackles not like?

Safflower and nyjer. In our food preference data Common Grackles score zero on both, meaning neither is a feeder food for them, while cardinals score safflower as a top-tier favorite and chickadees, titmice and house finches all eat it readily. Nyjer is not a substitute for a general feeder because only finches use it. Safflower is the workable swap because it keeps most of your regular seed-eaters and drops the grackles, the starlings and most squirrels at the same time.

How long does it take grackles to leave after I switch seed?

Give it 10 to 20 days. A flock that has been fed for weeks will keep checking the feeder for several days after the food changes, and the first three or four days often look worse than before because they land, sort through the safflower and dump it. Do not top up during that window, do not put out a second feeder with the old seed, and clear the ground every evening. Once the flock has checked three or four times and found nothing worth eating, it drops the stop from its route.

Will grackles eat suet?

Yes. Grackles rate suet as a food they eat readily, and starlings rate it top-tier, so an open suet cage is one of the first things a spring flock finds. The fix is geometry rather than food: a bottom-access suet feeder, where the cake is only reachable from underneath, is used comfortably by downy woodpeckers, chickadees, titmice and nuthatches and almost never by grackles or starlings, which do not feed upside down.

Are grackles protected? Can I trap them?

Common Grackles and Red-winged Blackbirds are native North American species and are federally protected in the United States and Canada, unlike House Sparrows and European Starlings. There are narrow agricultural exceptions in United States federal rules and they do not describe a backyard feeder. Treat lethal control as off the table and, if you think your situation is unusual, ask your state or provincial wildlife agency before you act rather than relying on anything you read online.

Why did grackles suddenly appear at my feeder in March?

They migrated in. Most of the Common Grackle population moves north in a fairly tight window from late February through April, and migrating flocks travel together and feed together. Your feeder did not change, the number of birds moving past it did. The same feeder that quietly fed six chickadees in January is now on the route of a flock of thirty, which is why the seed budget triples in a week with no other explanation.

Do short perches keep grackles off a tube feeder?

Partly, and at a cost. A perch under about 2 in gives a 115 g grackle nowhere to balance, so it will usually give up on that feeder. The same perch also excludes cardinals, which weigh about 45 g and need a large perch or a tray, and grosbeaks. If cardinals are the reason you feed birds, use safflower or a weight-activated feeder instead and keep the tray.

Sources and further reading

1. Common Grackle life history Cornell Lab of Ornithology, All About Birds Migration timing, flocking behavior and population trend
2. Discouraging unwanted birds at feeders Cornell Lab of Ornithology, Project FeederWatch Seed selection and feeder design as species filters
3. Migratory Bird Treaty Act protected species US Fish and Wildlife Service Which feeder birds are federally protected
4. Birds and backyard habitat guidance National Audubon Society General feeding and habitat advice