Irruptive Birds Migrate South

Cedar Waxwing
Cedar Waxwing US FWS FWS Digital Library, David Menke, Photographer
Every winter, many of Utah’s breeding birds migrate south to avoid the cold. After the warblers, tanagers, and orioles leave each fall, we share the snowy winter with hardier residents, such as chickadees, nuthatches, and juncos. But even hardier birds breed in the far north and venture south to Utah only during the most severe winters.

CEDW call, Western Soundscape Archive; University of Utah, Audio file copyright 2007, Kevin Colver. All rights reserved

Many people are familiar with the high, thin calls of Cedar Wawings. Less frequently heard in Utah are the slightly lower calls of their close cousins, Bohemian Waxwings.

Bohemian Waxwings(BOWA) call, Western Soundscape Archive; University of Utah, Audio file copyright 2007, Kevin Colver. All rights reserved

Bohemian Waxwing
Bohemian Waxwing, licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license. Source Wikimedia.org, Randen Pederson, Photographer.
Bohemian Waxwings are slightly larger than Cedar Waxwings, and a little fancier—their wing feathers include red, yellow, black, and white, and the underside of their tails is a rich cinnamon. Both species gather by the hundreds to eat berries, so you won’t miss a flock if there’s one nearby. Although waxwings are songbirds, the calls you hear don’t serve the same functions as true songs, advertising mate quality and defending territories. Instead, waxwings cooperate to find and feed on scattered fruit, their main winter diet. Unlike most birds, waxwings are able to smell, which may help them find their food. If waxwings eat berries that have begun to ferment over the winter months, they may become intoxicated even though their ability to metabolize ethanol is very high. The last time Bohemian Waxwings were abundant in Utah was during the winter of 2012-2013.

White-winged Crossbill(WWCR) call, Western Soundscape Archive; University of Utah, Audio file copyright 2007, Kevin Colver. All rights reserved

If you look in a pine tree, you may see a flock of White-winged Crossbills. Last abundant in Utah during the winter of 2008-2009, this species of finch forages on the seeds inside of conifer cones.

White-winged Crossbill, Courtesy and Copyright Paul Higgins, www.pbase.com/phiggins/
White-winged Crossbill
Copyright © 2009 Paul Higgins
More photos at pbase.com/phiggins/
and utahbirds.org Photo Gallery
As the name crossbill suggests, the lower part of its bill is bent to the right and the upper part to the left, allowing crossbills to wedge open pinecone scales and lift the seeds free with their tongues. In the winter, crossbills forage in flocks of ten to fifty. They quickly assess the quality of a tree’s cones, using visual and vocal cues from their flockmates, which are quiet when they are eating but chatter when they are not. When the volume of the chatter increases to a crescendo, all the crossbills in the flock know that it’s time to switch to a new tree. Unlike most songbirds, crossbills can breed at any time of year, as long as conifer seeds are abundant.

When the weather gets cold, keep an eye and an ear out for these winter nomads.

For Wild About Utah, I’m Andrew Durso.

Credits:

Waxwing Images: Courtesy US FWS, David Menke, Photographer
White-winged Crossbill Image: Courtesy and Copyright © 2009 Paul Higgins, Photographer
Text: Andrew Durso, http://www.biology.usu.edu/htm/our-people/graduate-students?memberID=6753

Additional Reading:

Fitting the Bill, Andrea Liberatore, August 11, 2011, https://wildaboututah.org/fitting-the-bill/

White-winged Crossbill, All About Birds, Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/White-winged_Crossbill/id

Cedar Waxwing, All About Birds, Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/Cedar_Waxwing/id

Bohemian Waxwing, All About Birds, Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/Bohemian_Waxwing/id

I Love the Four Seasons

Red Admiral Butterfly, Thomas G. Barnes, US FWS Digital Library
Red Admiral Butterfly
Thomas G. Barnes
US FWS Digital Library

Glacier Lilies
Erythronium grandiflorum
Copyright © 2010 Andrea Liberatore


I love the four seasons. Having spent my 72 years residing in the mid latitudes, I’ve learned to celebrate each of our seasons, but especially spring!

This is the rebirth flush with abundant water, new greenery, and air filled with bird song and sweet aromas as new flowers perfume the air hoping to lure in a pollinator.

With mid-April upon us and our 42 degree latitude, spring is in full swing here in northern Utah! Winter departs grudgingly slapping us with snow squalls intermingled with glorious, early summer days, a wild roller coaster ride which I truly enjoy!
I’m an avid phenology follower. Phenology is the study of how life adapts to seasonal changes. I revel in the first floral bloom, the first neotropical birds returning from Latin America with a heart full of song, and newly emerged, gaudy butterflies.

With a relatively stable climate, until recently, the timing of these events has evolved to near perfection
Let’s take a closer look at some of these phenomena. I’ll begin with our neotropical birds such as lazuli buntings, yellow warblers, and Western tanagers to mention a few. These species spend over half of their year in Mexico, Central and South America flying thousands of miles to for the breeding and nesting season in the Intermountain West. This may seem a bit extreme for these tiny flurries of life.

On closer inspection, you will find they have good reason for this daunting and dangerous task. The tropics have a relatively stable climate without the dramatic seasonal change that we experience. This results in relatively stable populations of flowers and insects, the primary food sources for most species. Further, the ratio of daylight to darkness is nearly constant with 12 hours of each. Our days lengthen as we journey toward summer solstice with nearly 16 hours of daylight! This allows a burst of energy to flow through ecosystems resulting in eruptive populations of insects and floral bloom. It also offers long hours of daylight for parents to gather food for their young which grow rapidly toward fledglings, thus reducing the possibility of predation and also preparing them for the arduous flight south as fall approaches.

Let’s examine flowers and insects. With our very warm winter and spring, I was expecting a much earlier arrival of both and was not disappointed. I counted 17 species of flowers by the second week of April! And butterflies were on a similar schedule with 9 different species during the last week of March- remarkably early! Although delighted, it occurred to me that returning birds may not be so pleased. If the flowers begin to fade, and insects begin their downward slide at the peak of birds rearing their young, trouble is afoot! A five year Audubon study revealed that 1/3 of our birds are predicted to be severely impacted by these rapid climate shifts.

On a more positive note, spring will continue as will bird song, vernal waterfalls, eruptions of wildflowers and butterflies. And spring repeats itself as we move to higher elevations. As cornices on our mountain ridges recede, up pops flowers for yet another spring bloom, and with them butterflies, bees, and birds!

Credits:

Pictures: Courtesy Dr. Thomas G. Barnes, US FWS
Pictures Lilies: Copyright © 2010 Andrea Liberatore
Audio: Courtesy and Copyright Kevin Colver
Text: Jack Greene, Bridgerland Audubon Society

Additional Reading:

https://wildaboututah.org/usa-national-phenology-network/