Hummingbirds Weighty Stuff The following chart shows the weights (grams) of summer and winter Ruby-throated and Rufous Hummingbirds, and American Robins for comparison: Average Weights in Grams Winter Male Breeding Male Winter Female Breeding Female Rufous Hummingbird 3.27 3.34 3.35 3.58 Ruby-throated Hummingbird 3.08 3.36 3.17 3.81 American Robin 86.2 84.8 83.6 75.0 Think about what these numbers mean, and about the different problems faced by robins and hummingbirds as you answer these questions: Which are heavier: male or female hummingbirds? Which are heavier: male or female robins? Why the difference between hummingbirds and robins? Which are heavier: winter hummingbirds or breeding hummingbirds? Which gains more weight in spring: male or female hummingbirds? Why do you think this is? Which loses more weight in spring: male or female robins? Why do you think this is? Which are heavier: winter robins or breeding robins? Why the difference between hummingbirds and robins? See our answers and discussion here. Facebook Pinterest Twitter © 1997 – 2019 Journey North. All rights reserved.