Read the passage about bird food and bird watching. Noted scientist Dr. Elsa Birde described the effect of adding a mixture of d
ried apples and raisins to the previous feed of sunflower seeds, millet, thistle seed, and cracked corn in bird feeders in her yard. Over three years, Dr. Birde observed that the new mixture increased the number of songbirds at her feeders, especially during the months of April and May. As she has done for several years, Dr. Birde recorded, at the same time each day, the number of birds at each of her four feeders. She noted that the third year using the mixture coincided with the largest increase. There was a twenty-five percent increase in the number of songbirds over times when this mixture was not used. Dr. Birde also noted that in the third year she used a specific ratio of the ingredients, carefully measuring, which she had not done in previous years. The third year also had a warmer than normal spring, and a construction project began in a neighborhood near Dr. Birde’s. Dr. Birde is now going to produce this formula for sale and advertise to customers that they may see the same twenty-five percent increase in songbirds at their feeders. Dr. E. Birde, Journal of Scientific Bird Feeding Which might be a cause for the increase in songbirds at the feeders?
A) the time of day that the birds were counted at the feeders
B) the addition of dried apples and raisins to the formula
C) the temperature changes each year
D) the increased number of bird feeders
B) The addition of dried apples and raisins to the formula.
Explanation:
Based on the excerpt above, Dr. Elsa Birde noticed the increase in the number of songbirds in his bird feeders after she added the new mixture into the feeds. Addition of mixture of dried apples and raisins in the usual feed of sunflower seeds, millet, thistle seed and cracked corn was a new plan of hers to try out on the birds. And she found that it was successful in bringing about the increase in the birds. Also, this increase is not just a one time thing. She kept recording the result for more than three years and the results remained the same. That is why she is also planning put the formula into production for others to experience the same increase. Thus, it can be safely said that the increase in the songbirds at the bird feeders is due to the addition of the new mixture to the formula.
