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Nick Crouch

I am a postdoctoral research scientist in the Clarke lab at the University of Texas at Austin, principally interested in avian evolutionary ecology. My doctoral work focused on a monophyletic clade termed Telluraves (the 'earth birds') which comprises most extant species. I am expanding the taxonomic scope of my work to include palaeognaths — some of the oldest lineages of birds, e.g. rheas and kiwis, as well as some spectacular extinct species, e.g. elephant birds. I generally employ phylogenetic comparative methods, utilizing a combination of life history, molecular, and paleontological data. Using these methods, I am interested in asking a variety of questions about how species traits have changed over deep time, including both the way in which traits affect biodversity through time and, reciprocally, are affected by changing biodiversity. I also like to develop scripts for the statistical program R for analyzing and visualizing my own data as well as for use by the scientific community.

Publications R Code Contact

Research questions


How does including fossil taxa into phylogenetic comparative methods change our understanding of the evolution of birds? What are the differences in ecology between extant and fossil taxa? How quickly has avian ecology changed over time?

Early avian evolution

When did the major lineages of birds originate? How does continued development of methods of calibrating phylogenies change estimates of origination? How does the inclusion of fossil taxa change these estimates?

Ecological specialization

How can we try and better quantify ecological specialization? How does taxonomic revision impact delimitation of specialization? How does specialization influence the diversification of lineages?

Evolution of song

How do abiotic and biotic factors affect song complexity? How has song evolved over deep time?


A list of publications can also be found on Google Scholar
A copy of my CV can be downloaded here
A link to my ORCiD page is here


In review

Crouch N, Igić B, Ricklefs, R. E. in review, Specialization is associated with increased extinction rate in birds

Crouch N, Ramanauskas K, Igić B, in review, Investigating the effect of tip-dating on the age of the avian tree

Crouch N, Mason-Gamer R, in review, Investigating spatial variation in elements of song complexity in songbirds

Crouch N, Capurucho J, Hackett S, Bates J, in review, Visualizing pattern and inferring process for Neotropical diversity


Crouch N, Mason-Gamer R, 2018, Structural equation modeling as a tool to investigate correlates of extra-pair paternity in birds, PLos ONE, 13 (2), e0193365 Link

Widhelm T, Huang J P, Sérusiaux E, Moncada B, Lücking R, Mercado-Díaz J A, Magain N, Goffinet B, Crouch N, Mason-Gamer R, Bertoletti F R, Asztalos M R, Lumbsch T H, 2018, Oligocene origin and drivers of diversification in the genus Sticta (Lobariaceae, Ascomycota), Molecular Phylogenetics and Evolution, 126, 58--73 Link

Thomson C E, Bayer F, Cassinello M, Crouch N, Farrell S, Heap E, Mittell E and Hadfield J D, 2017, Selection on parental performance opposes selection for larger body size in a wild population of blue tits, Evolution, 71 (3), 716--732 Link

Hadfield J, Heap E, Bayer F, Mittell E, Crouch N, 2013, Disentangling genetic and prenatal sources of familiar resemblance across ontogeny in a wild passerine, Evolution, 67 (9), 2701--2713. Link

Hadfield J, Heap E, Bayer F, Mittell E, Crouch N, 2013, Intra-clutch differences in egg characteristics mitigate the consequences of age-related hierarchies in a wild passerine, Evolution, 67 (9), 2688--2700 Link

R code

Below are a collection of functions I have written to perform a variety of tasks in R. I will continue add to, and modify, this list over time.

sandhill cranes flying

R packages

RDH: Range data helper. A package designed to aid in the analysis of spatial data. The package is available via GitHub

I have also contributed code snippets to paleotree and rwty

Individual functions

Oct 24th 2014
phylo.diversity : Will calculate diversity of groups through time, given a phylogeny and information on which groups the species belong to.

Dec 9th 2014
add.tip.icons : Plot discrete species characters onto a phylogeny.

Jan 15th 2015
add_HPD_info : Add posterior age distribution information to specified nodes on a phylogeny Updated Nov 2nd 2015 .

Feb 24th 2015
base.line.values : Calculate base line origination and extinction values, following Foote (2005).

Sept 8th 2015
unique_sister_spp: Calculates the number of unique sister species for a range of species across a set of phylogenies. This function is currently being implemented in the R package rwty.

Oct 8th 2015
color.terminal.branches: Color only the terminal branches in a phylogeny by corresponding species trait values Updated Jan 26th 2017 .

Feb 16th 2016
calculate.ellipse.area: Calculate the amount of morphological space occupied by taxa.

Sept 20th 2016
migration.distance: Calculate the migration distance for a specified species.

Aug 16th 2017
mirror.barplot: Make a mirrored barplot for comparing positive and negative changes in a variable.

Aug 18th 2017
make.node.age.df: Extract node age information from an annotated phylogeny.


The University of Texas at Austin
Department of Geological Sciences
2275 Speedway Stop C9000
Austin, TX 78712–1722.

it's Nick