PEEC Amateur Naturalist: Taking Flight

Jorge Ayarza from Colombia is teaching students about catching and handling birds with mist nets. Here the students are having a hands-on experience with the soft bags that are used to safely transport birds from the nets to the data collection area. Photo by Stephen Fettig
 
Maria del Pilar González Barroso from Mexico and Diego Alejandro Cueva from Colombia view a Townsend’s Warbler just before releasing it back into the wild. Photo by Stephen Fettig
 
PEEC Amateur Naturalist: Taking Flight
By ROBERT DRYLA

Particular thanks to Bandelier National Monument, Stephen Fettig, and the Park Flight program

A couple of weeks ago the weather was sunny and hummingbirds gathered the same as usual at their feeders. A few days later the weather was still sunny but no hummingbirds were to be seen. The hummingbirds had begun their annual migration south. But what had motivated them to leave? The weather was still pleasant.

Hummingbirds instead sense the length of day, and when the days become short enough, hummingbirds leave. But are they primarily migrating to where flowers still bloom or are they primarily avoiding cold weather—or are other factors at work?

One way to answer this question involves banding birds and counting species from year to year. For example, researchers find that the Rufous and three other species of hummingbird migrate to southern Mexico and Guatemala. However there has been a steady increase in Rufous Hummingbirds remaining during winter, especially along the warmer east coast.

The thought is that more hummingbird feeders are being set up and people are leaving the feeders later into the autumn. Rufous Hummingbirds evidently may stay if food is available, even if the days are becoming shorter and weather is becoming colder. You may go to the following web site to learn more:  http://www.rubythroat.org

What about other bird species in New Mexico? Birds migrate without concern to national boundaries. Bird populations also are affected by what is happening ecologically from country to country. As an example, Swainson’s Hawklives in New Mexico and migrates to Argentina.

Swainson’s Hawks eat insects and may absorb insecticide poisons such as DDT that were meant for insects. Although DDT stopped being used in the United States, it continued to be used in Argentina, resulting in the population decline of this hawk. An international and educational perspective is a part of monitoring migratory birds.

Bandelier National Monument conducts a bird banding program called Park Flight. Two biology interns have come for the summer from Central and South America for the past nine years. A similar program is conducted at Mesa Verde National Park.

The surprise is how much variability occurs although the environments appear to be similar for Bandelier and Mesa Verde. Eighteen species have been captured at Bandelier and twenty-one species have been captured at Mesa Verde. Of the four dominant species for each place, only the Chipping Sparrow is dominant in both places.

Four Dominant Bird Species, Bandelier

Four Dominant Bird Species, Mesa Verde

 

Audubon’s Warbler

Gray Flycatcher

Chipping Sparrow

Black-throated Gray Warbler

Gray-headed Junco

Chipping Sparrow

Hermit Thrush

Juniper Titmouse

Chipping Sparrow. Courtesy/Real Animals Life

The number of birds captured from year to year also can vary greatly. The following table shows that the number of birds banded at Bandelier decreased dramatically from 2010 to 2011. Was this a result of the Las Conchas forest fire in 2011?

Year

Total Banded Bandelier           

Total Banded, Mesa Verde

 

2010

361

255

2011

122

253

2012

249

182

Data may help in understanding what is happening to birds, but it is seeing birds in their natural settings  that makes people care for them. The Park Flight program therefore has school students come to its capture sites to see how birds are caught in mist nets and then how bands are put their legs. A total of 312 students participated this past school year. The students came from four of elementary schools and the home school group in Los Alamos as well as from two schools of the Jemez Pueblo.

The high point of a trip is when the students release a bird after it is banded. A bird may sit quietly for a while in a student’s hand then suddenly take flight. Photo by Robert Dryja
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