Maggie MacPherson’s poster at SICB 2017

Maggie MacPherson presented a poster on the evolution of migrationof Tyrannus flycatchers at this year’s Meeting of the Society of Integrative and Comparative Biology, January 4-8, 2017, New Orleans, Louisiana, USA:  macpherson-sicb-2017

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Diego Tuero’s poster at ISBE2016

Our colleague from the Universidad de Buenos Aires, Diego Tuero, presented the following poster on sexual selection in Fork-tailed Flycatchers (Tyrannus savana) at the 16th Congress of the International Society for Behavioral Ecology (

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Poster presentations at NAOC2016

From 17 to 20 August 2016, several of us participated in the sixth North American Ornithological Conference (, held in Washington DC. Three of the posters we presented on various aspects of Fork-tailed Flycatcher ecology are shown below. The first is a poster by Vanesa Bejarano on the relationship between the timing of feather molt and reproduction among different populations of flycatchers. Another poster presented by Maggie MacPherson shows the relationship between flycatcher migration and climate across South America. Finally, Alex Jahn presented a poster showing recent data suggesting that some flycatchers that breed in Brazil begin their flight feather molt in southwestern Brazil before migrating to northern South America. All three of these studies will soon be in review for publication in research journals.

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What is the relationship between climate and flycatcher migration?

How climate affects the timing of bird migration is a key question in the study of migratory bird ecology. One of our colleagues, Maggie MacPherson, a PhD candidate at Tulane University, is modeling how Tyrannus flycatchers track rainfall vs. temperature across the Western Hemisphere. See her website for animated maps showing how Eastern Kingbirds (Tyrannus tyrannus), Tropical Kingbirds (T. melancholicus) and Fork-tailed Flycatchers (T. s. savana) track temperature vs. rainfall throughout the year.

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Vichada, Colombia 2016

Over the last several weeks, migratory Fork-tailed Flycatchers (Tyrannus s. savana) have been migrating from their breeding grounds in southern and central South America to northern South America, where they will spend the austral winter. In search of these migrants, José Ignacio Giraldo and Jonathan Candil Méndez visited several ranches (Villa Lorena, El Caribe, and El Brillante) near the town of Santa Rosalia in Vichada Department, eastern Colombia, from 11 to 20 April, 2016. They saw flocks of dozens of Fork-tailed Flycatcher migrants passing through, apparently feeding on fruit, and were able to band a few.


Vichada Department, Colombia

José Ignacio and Jonathan were also able to catch a few of the resident subspecies of Fork-tailed Flycatchers (T. s. monachus), which are lighter-colored than the migratory subspecies. Very little is known of the ecology and breeding behavior of this resident subspecies. Although José and Jonathan searched for nests they did not locate any, even though this is supposedly the time of year when this subspecies breeds.

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Fork-tailed Flycatcher of the subspecies monachus, in Vichada Department, Colombia

Notably, on the morning of 15 April they also saw a large flock of about 500 Bobolinks (Dolichonyx oryzivorus) in grassland habitat. This is an increasingly threatened species that breeds in North America and overwinters in South America (south to Argentina). Given that spring is now underway in North America, this flock of Bobolinks were likely migrating back to their North American breeding grounds.

We thank the owners of the ranches visited for access to their property and hope to return again soon.

Bobolinks Colombia Apr 2016

Flock of Bobolinks migrating through Vichada Department, eastern Colombia, April 2016

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Flycatcher migration in Tucumán


Migrating Fork-tailed Flycatchers in Tucumán, Argentina, February 2016 (Photo: Emanuel Pérez Bogado).

Last week, one of our collaborators, Emanuel Pérez Bogado, a graduate student in Patricia Capllonch’s lab at the Universidad Nacional de Tucumán, Argentina, saw flocks migrating Fork-tailed Flycatchers in northern Argentina (Tucumán Province). One flock was of about 50 birds, including both adults and first-year individuals. These birds head northwards at this time of year, having spent the austral summer (October-January) breeding across much of central and northern Argentina. They primarily overwinter in the “llanos” (grasslands) of the Orinoco River Basin (e.g., Colombia and Venezuela), where they molt their flight feathers before returning to southern South America beginning in August.


Migrating Fork-tailed Flycatchers in Tucumán, Argentina, February 2016 (Photo: Emanuel Pérez Bogado).

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Mato Grosso do Sul 2016

Light-level geolocator data from Fork-tailed Flycatchers (Tyrannus s. savana) breeding in central Brazil indicate that some flycatchers spend a month (late January to mid-February) in southwestern Brazil, before migrating to northern South America to overwinter (unpub. data). So, from 6-12 February, 2016, Andre Guaraldo and Alex Jahn searched for Fork-tailed Flycatchers in the state of Mato Grosso do Sul in southwestern Brazil, hoping to find a roost at which they could be captured. After four days on the road and about 1800 km traversed, a roost was spotted south of the town of Dourados, at Fazenda Ribalta. Much of the landscape is covered by fields of soybeans, but this ranch has several bamboo groves in which at least 100 flycatchers roost at this time of year. We managed to catch 4 individuals (two adults and two hatch-year flycatchers). One of the adults was molting the first primary feather on each wing (see figure), supporting the idea that at least some Fork-tailed Flycatchers stopover in this part of the continent to begin their molt before heading to the wintering grounds in the grasslands of the Orinoco Basin (Colombia and Venezuela), where they complete the molt.


Tall mist net set up next to a bamboo grove where migratory Fork-tailed Flycatchers (Tyrannus s. savana) roost in Feb 2016.


Soybean field in Mato Grosso do Sul, Brazil.


Wing of female migratory Fork-tailed Flycatcher (Tyrannus s. savana) captured at Fazenda Ribalta, Mato Grosso do Sul (Feb. 2016). Note molting feather (First primary).


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