Blackbird Gift Sacs

Published on March 1, 2014

I have devoted the better part of my life to studying wildlife and have always had a deep love and respect for nature. In my view, any critter that crawls, walks, swims or flies is interesting and belongs on Earth.

That was my belief until I met up with the Common Grackle (Quiscalus quiscula), or blackbird, of the Midwest. These birds and I simply cannot get along when it comes to water gardens. A grackle’s reason for visiting our water gardens is, plainly speaking, gross!

So just what is the problem? Simply put: fecal sacs! This is a sac consisting of a membrane that contains the feces of the bird’s young. When a young nestling Grackle defecates, it comes out contained in a nice little package. The parent birds have developed a practice of picking this sac up, flying off with it and depositing it in or near water. We have been so gracious in providing water in very convenient locations, but they will fly quite a distance carrying these sacs and neatly place them in a personal “deposit area” in, or on the rocks around, your water garden. Each deposit area can have dozens of white poop spots!

These areas next to a water garden are the spots where a couple different pairs of grackles deposit their fecal sacs. This amount of poop is deposited every day. It is recommended to wash off these areas on a regular basis to maintain the beauty of the water garden.

Young defecating in fecal sacs is common in other species of birds as well, but these other species do not necessarily carry the fecal sacs to water. Grackles may deposit these sacs in areas away from water but I have not witnessed it. If water is close by, they will take these gifts to it. So, with grackles and ponds you have bird poop everywhere — the amount depends on the number of Grackle nests in your neighborhood.

Nesting Season
During the nesting season, Grackles most often nest in evergreen types of trees. If you have large evergreens in the eastern two thirds of the U.S. you will have Grackles nesting in them. Grackles are solid, glossy blackbirds with an iridescent purple sheen around the head. They are a common type of native bird and form huge flocks during migration, but during the nesting season they are territorial and spread out. There can be as many as a half dozen nests in a couple of acres. The more evergreens there are in your neighborhood, the more Grackle fecal sac deposit areas you will have. I have seen up to seven deposit areas around the perimeter of a pond, with yet another set of parent birds flying over the pond dropping the fecal sacs in the water.

You can easily determine the number of nests in the area by the number of “spots” where the fecal sacs are deposited. As mentioned, each bird will fly to the same spot for every fecal sac trip. Once this behavior is recognized, you can predict that a Grackle will show up regularly at its deposit area. It is relatively easy to get photos due to this type of consistent behavior. When the young get older and about ready to fledge, the parent birds make a fecal sac trip every three to 10 minutes depending on the number of young. They poop a lot as they get older, and those parent Grackles have their work cut out for them providing food and dutifully carrying away their diaper sacs.

When I first suspected that the problem of these deposited bird droppings was not unique to my water gardens and those of my clients, I called a former professor of mine who is an avian ecologist. I asked him about this type of Grackle behavior and he had an interesting story to relate. He said that he once had a black-matted trampoline in his yard and the Grackles were depositing the fecal sacs on the surface of that shiny black mat — making a huge mess. He said that he initially thought they were putting them there due to the fact that the trampoline was “proximal” (near) to the nest and more convenient for them, so he moved the trampoline more “distally” (distant) and they still flew to it to drop their fecal sacs. Those were his words, and in more simple layman’s terms he thought it was too close to the nest so he moved it much farther away. After our conversation he and I came to the same conclusion: the shiny surface resembled water, and for lack of more convenient water, they chose the trampoline surface to drop off their little gifts.

I have since done my research and found out that almost every water gardener I know in the Midwest has this problem in the spring. It’s frustrating. I have even known some water gardeners who resort to shooting the birds, and that is sad due to the fact that they have babies back in the nest.

But Why?
So why do the birds do this? The behavior is an innate housekeeping practice that is not only hygienically smart, but helps avoid luring predators to their nests. Also, after the sacs are deposited the parent bird will “wash” its beak and then take a drink of water.

Male Grackles show a more blue iridescence on their heads than the females do, but they both have the reflective color. They are not all black. The male in this photo is on the left.

I have seen Grackles drop these sacs while flying over water. Koi seem to like the taste of them because the water will seem to boil as they fight to eat the sacs! This could be a possible parasite introduction to the fish. I have also seen Grackles fly over vehicles and drop the sacs there. I believe that they were thinking the shiny vehicles were water, similar to the trampoline. All birds are creatures of habit and will fly the same route and land in relatively the same spot every fecal sac trip! With four to six babies in the nest, this can be a lot of white poop spots on your rocks — and this is for just one nest.

This amount of bird poop washing into your pond from the surrounding rocks, or from deposits directly into the pond, can create pea-green soup water. Of course, the amount depends on the size of the water garden and number of nests — and consequently, the number of fecal sacs deposited.

So what can you do to prevent them from doing this? Nothing, really. You can’t prevent the behavior; you can only try to deal with the mess. It only lasts for a month, and when the young fledge the nest the problem goes away. It’s unsightly around your pond, but it does wash off. Rain will eventually wash it away, but for a more active approach I recommend, on a regular basis, scrubbing the rocks around your pond and netting out the sacks that have been placed in the water. The sacs stay intact for a day or two in the water, unless the fish get to them and eat them first.

Now you know more than you ever wanted to know about Grackle poop and how it can affect your water garden. You can say now that you have read it all!

Japanese Koi Kodama

2 thoughts on “Blackbird Gift Sacs”

  1. Stephanie Besch

    We don’t live near water, have a pond nor anything shiny that might be confused for water. Grackles are dropping their decal sacs on our deck and chairs. Very frustrating and don’t know how to deter them,

  2. I really do not have a solution for you other than to be patient and as soon as the baby grackles fledge the fecal sacs will stop. I t will only be another week or so. So keep the scrub brushes handy for awhile. Good luck. Jamie

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