Rice Researchers In Africa Trying To Get Ahead Of Birds

In parts of Africa, rice farmers say that the 2 biggest yield robbers they face are weeds through the season and birds that feed on maturing grain. As researchers with AfricaRice find, the 2 go hand in hand.

More weeds, more birds, more loss.

This is a different kind of bird problem than we face in the American South, of course. Bird problems here – usually related to blackbirds – occur in the spring when flocks descend on newly emerged rice and consumed seedlings.

Yet, some of us are old enough to remember the extreme measures farmers once employed to clear away birds on maturing rice. Carbide cannons, for example, were one ploy for a while. As a teenager growing up in Bolivar County, I can remember a farmer giving me a block of .22 shells so that I could shoot at blackbirds over this rice. Looking back, I doubt it I had much effect, partly because I wasn't a good shot and partly because the birds knew to move away from me.

African rice tends to be grown in such a way that even a small amount of bird feeding can cause significant yield loss. Much of the crop is rain fed, with minimal fertilizer inputs. With low yields predetermined, it wouldn’t take a lot of feeding to cut noticeably into production.

Based on surveys conducted with farmers in the Senegal River Valley, estimated average bird damage at 11.2% of the potential rice yield in 2003-2007.

Researchers with AfricaRice, a research center that works across several African countries, picked up on the connection between weeds and birds by surveying farmers. The growers said that weedier fields tended to have the most bird damage.

To understand the relationship, the research team set up a series of plots that included:

• No control of either weeds or birds.
• Only bird control (plots were covered with nets).
• Only weed control (hand weeded every ten days).
• Full control of birds and weeds.

Researchers set up the experiment with early and late maturing rice varieties, according to an article posted on the AfricaRice web site.

Results, the article noted, were fairly straightforward: “The weed-free fields discouraged birds. Weedy fields, on the other hand, attracted birds. The birds fed on weed seeds, found shelter in the weeds, and perched on the weeds to eat the rice. Weed-free, early maturing varieties suffered little from bird attacks. If the rice matures late, it is ripe when the weeds seeds are all gone, and the birds then turn to the rice grains.”

At least in Africa, little research has been conducted on bird-damage prevention.

“Pest management scientists tend to ignore birds, and ornithologists tend not to think of birds as pests,” the article pointed out. “Therefore, far too little research is done on birds as pests. This (AfricaRice) research, although in an early stage, suggests that farmers have several options to manage birds.”

Here’s a link to the full article.

- Owen Taylor