Editor’s note: This tip was provided by Roy Williams, a member of the Dairy Calf and Heifer Association.
Birds can cause serious economic losses to dairy operations through three different routes: (a) predatory birds kill calves; (b) many birds eat large quantities of feed; (c) all birds can carry Salmonella and other diseases.
While attacks by eagles are relatively rare, there have been documented cases where a single eagle, or a nesting pair of eagles, has been responsible for over 30 attacks on calves in a short period of time. In these cases, federal authorities have trapped the responsible birds and moved them to an area where the birds would not cause more trouble. Eagles will kill adult deer, and calves as large as 250 pounds have been killed by eagles. Eagles can be a problem throughout the western half of the U.S.
Vultures are common in most areas of the U.S., and cause significant calf and cow losses by attacking newborn calves and cows in the final stages of labor. If you see vultures around very young calves in your maternity pen or pasture, you are at high risk for loosing calves to vulture predation. Vultures are attracted to birthing fluids and will attempt to eat any flesh that they find near birthing fluids, thus leading to severe injuries to cows and death of calves. Vultures are protected under Federal law. Killing of vultures or eagles is a criminal act with severe penalties including imprisonment. There are no reliable vulture control procedures. If you are having newborn calves attacked in your fields, your only reliable response may be to move your maternity operations into an area inaccessible to vultures. Magpies are also known to kill calves.
Most birds around a dairy or calf facility are attracted to the availability of water and grain, often in the form of protein pellets. Effective control of birds consists primarily of making water and feed inaccessible (or at least as inconvenient as possible) to the birds. Starlings are the most numerous pest birds in many areas, but pigeons are also very common on dairies. Starlings may travel 30 miles or more between roost and food supplies, so elimination of roosting areas near the dairy will not be a successful method of reducing starling populations. A flock of 300 starlings will eat a ton of grain per month.
All birds may carry Salmonella, including Salmonella Typhimurium DT 104 (which is highly antibiotic resistant) and Salmonella Dublin, which causes not only scours but also is a significant cause of respiratory disease in cattle. Bird droppings contaminate water troughs and feed bunks, and exposed feed in storage areas. You should make every effort to prevent birds from being in places where they can leave droppings in water troughs, feed bunks, and feed supplies.