Birds go to corn fields when the corn is approaching the V1 stage, were you can see the first leaf collar, and start trying to pull the seedling plants out of the ground.  If they are successful you will see a seedling plant with no seed hanging on by a few roots, maybe a wilted or dead plant or may be none because it has all but dried up and blown away.  You may find parts of the seed coat remaining, easily visible because of seed treatment color and you may seed a depression or divot where the bird worked the seedling around in the ground until it could get to the seed.  Sometimes all that is left is this hole or depression but you can see them nicely spaced out where your corn plants should be.

This hole or depression the birds create may also contain a plant that has been cut off as the birds were unable to work the seed out of the ground and they ended up clipping off the green shoot.  That clipped green shoot takes less than a day to dry up and in many instances blow away.  Get out a knife or a hand spade and dig around the depression you may still find an intact growing point and seed; the growing point is .75 inches below the soil surface and by this time you may see some swelling as the plant starts to form its first nodal roots.  You may also find the birds have reached that deep and clipped the growing point off and now the plant is dead.

A first line of defense when it comes to seed loss from birds is making sure that you have corn planted at least 1.5 inches deep and I prefer 2 inches.  Maybe 1.5 is considered and ideal "book" depth but here are two real world thoughts.  One I have great appreciation for the modern corn planter's ability to place seed exactly 1.5 inches deep but if you are down measuring seed depth seed is usually going to be in and around 1.5 inches, more or less.  What you want to be hitting 100 percent of the time is greater than 1.5 inches because anything less that means you have some seed around 1-1.25 inches.  Seed that shallow and under the right conditions is easier for the birds to pull up. Aiming for 2 inches will guarantee the majority of your seeds are placed 1.5+ inches.

First year corn planted into sod ground that has worked up nice and loose often gives up corn plants very easy to birds.  Worn double disk openers or those that are not adjusted together properly may prevent the seed from reaching the proper depth.  Don't be surprised to see patterns in a field where looser soil areas are damaged and more compacted area less so.  It may also be hard to get the desired seed depth especially notilling into gravelly soils.

There is another factor when it comes to the "blackbirds" (crows, redwing blackbirds, starlings and grackles) that cause the damage and that is a place for them to roost. Fields that are under bird pressure year after year usually are the right combination of trees available for birds to roost and a food source.

So if you have exhausted getting planter right then consider the use of Avipel® Corn Seed Treatment. Avipel's active ingredient anthraquinone is a chemical found in plants such as rhubarb.  When applied to seed and consumed it causes birds stomach distress to the point they will leave the area.

Over the past two years my extension co-workers in Cornell Cooperative Extension and I along with New York State IPM staff like Ken Wise have put out plots where the same hybrid with and without the Avipel®.  

The product works very well, so well that when selecting fields that had consistent damage and placing strip trials in those fields the birds once eating the treated strips tended to leave both treated and untreated alone.  Don't get any ideas here, I have seen birds figure out the second, fourth and fifth rows of a six row planter were shallow planted and eliminate those rows and not the others planted deeper.  

Avipel® Hopper Box Corn Seed Treatment may be purchased and used in NY to reduce grackle and blackbird damage to field and sweet corn. Users must have the 24(c) Special Local Need Registration label in their possession when using this product. (The NY Special Local Needs registration number is SLN NY-170006.) The Special Local Need registration is due to the NYSDEC recognizing that bird damage to corn is a significant issue in NY and that there are no other NY-registered pesticide products to address the situation. Seed pretreated with Avipel® is available from some  seed companies so talk to your seeds person to see if that is a possibility if you do not wish to treat your own.

Cost for the hopper box treatment is in the range of $7.50 to $8.40 an acre depending on any discounts. So figuring the cost is equal to the value of 2-3 bushel of corn if you have fields or parts of field that are being wiped out by birds the cost recovery on the Avipel® is very easy to achieve.

Starting with increasing seeding depth should not only lead to less bird damage but also improve corn growth and development in your fields.  But if birds are a problem taking corn seeds then consider the Avipel® seed treatment to reduce if not eliminate the damage.

Curtis, P. D., K. L. Wise, J. Cummings, A. D. Gabriel, K. Ganoe, J. J. Miller, M. E. Hunter, K. A. O'Neil, J. R. Lawrence, P. E. Cerosaletti, and Dale R. Dewing. XXXX. Field evaluation of anthraquinone treatment to reduce corn seedling damage by birds. Crop Protection (in review)