Neighborhood Critters – Tree Swallows

Marcie and her tree friends know about global warming.  They watch their animal buddies try to adjust to our planet as it gets hotter.  Global warming affects wildlife in numerous ways.

As the temperature increases, many animals are moving to colder regions or higher elevations, where more tolerable conditions exist. These changes have made survival for some species more difficult.  Unfamiliar species are brought into contact with each other, often resulting in new and direct competition.  Changes in food quality or in availability of breeding sites are also likely to result.  Some species are disappearing from southern or lower elevation portions of their native habitat.

Extinction can occur when a species is unable to adapt to changes in its environment. One example is the polar bear.  Polar bears have been affected by loss of Arctic ice caused by global warming. Polar Bears need ice floes to hunt seals and other prey; without ice floes,  the polar bears will starve.

Familiar urban wildlife has been affected by global warming, too. In fact, it is changing the behavior of a bird that lives in our own yards and urban forests.  The tree swallow (Tachycineta bicolor) is a bird that can be seen across the U.S., including throughout Southern California in the winter.  Earlier springs and warmer temperatures have caused tree swallows to lay eggs more than a week sooner than usual.  Tree swallows act as weather monitors, according to scientists, because they hunt insects “on the wing”. They are “income breeders” that rely on their daily foraging intake. Insects the swallows need do not fly during cool weather so when the weather grows hotter and the insect population increases, the swallows begin their new families. Earlier breeding is a signal that the Earth is indeed warming.

How will this affect the swallows and other interrelated animals? What happens when the tree swallow no longer travels this far south? Will we become inundated with the millions of insects that it would normally eat? We do not yet know and must wait for more observations from Marcie and concerned scientists around the world.

Could you recognize a tree swallow if you saw one?

Stature:  This song bird is small and slender ranging between 5-6 inches. Wingspan is 12-14 inches. It is white underneath and shiny blue-green on the top. The face is dark and throat is white.

Habitat:  It spends winters throughout southern California, South Carolina, Florida, and the Gulf Coast southward to Panama. It breeds in the late winter as it turns warmer for spring. The tree swallow prefers open areas near water and fields and will nest in a tree cavity or nest box.

Food:  Flying insects and some berries. It forages and catches insects in flight.


Signs of Global Warming:

  • When Greenland’s glaciers slide as they melt, they create earthquakes. Over the past 5 years, the number of quakes has doubled. LaMont-Doherty Earth Observatory at Columbia University.
  • In the 1st 75 years of the last century, the average temperature increased 0.80 C but the increase dramatically accelerated in the century’s last 25 years to 0.60 C. The annual warming acceleration rate more than doubled. NASA’s Goddard Institute for Space Studies.
  • The Earth’s warming coincides with rapid growth of human-made greenhouse gases. Goddard Institute.
  • 160,000 people, primarily children, die each year as a result of global warming. This is 440 deaths per day!  World Health Organization.


Oven Cleaner:  Sprinkle baking soda on moist surface and use steel wool to scrub. Or use Arm & Hammer Oven Cleaner, which Consumers Union has declared to be nontoxic.



To empower young people to be environmental leaders