diversity Article Sex and Age Effects on Monk Parakeet Home-Range Variation in the Urban Habitat Juan Carlos Senar 1, * , Aura Moyà 1 , Jorge Pujol 1 , Xavier Tomas 1 and Ben J. Hatchwell 2   Citation: Senar, J.C.; Moyà, A.; Pujol, J.; Tomas, X.; Hatchwell, B.J. Sex and Age Effects on Monk Parakeet Home-Range Variation in the Urban Habitat. Diversity 2021, 13, 648. https://doi.org/10.3390/d13120648 Academic Editor: Luc Legal Received: 25 September 2021 Accepted: 3 December 2021 Published: 6 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Museu de Ciències Naturals de Barcelona, Pº Picasso s/n, 08003 Barcelona, Spain; aura.moya.4@gmail.com (A.M.); jpujoldelrio@gmail.com (J.P.); fxato@hotmail.com (X.T.) 2 Ecology, Evolution and Behaviour, School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK; b.hatchwell@sheffield.ac.uk * Correspondence: jcsenar@bcn.cat Abstract: Home-range size is a key aspect of space-use, and variation in home-range size and structure may have profound consequences for the potential impact of damage and control strategies for invasive species. However, knowledge on home-range structure of naturalized parrot species is very limited. The aim of this study was to quantify patterns of home-range variation according to sex and age of the monk parakeet Myiopsitta monachus, an invasive parakeet in Europe. Mean kernel home-range size was 12.4 ± 1.22 ha (range 1.7–74.1 ha; N = 73 birds). Juveniles had a larger home-range size than adults, but sexes did not differ in kernel home-range size. The mean maximum distance moved by monk parakeets was 727 ± 37.0 m (range: 150–1581 m), and it was not dependent on either the sex or age of the birds. Having a small home range is one of the conditions for the feasible eradication of an invasive species; hence, the small home range of urban monk parakeets that we report here is good news for pest managers. However, this small home-range size can limit the effectiveness of culling operations with traps or feeders with contraceptives or poison, and other alternatives, such as funnel nets or traps, should be used. Keywords: Myiopsitta monachus; home range; sex; age; urbanization; invasive alien species 1. Introduction Animal movement and space-use is a key topic in ecology [1]. Early work mostly focused on describing movement patterns and their links with external factors (e.g., the environment), neglecting the individual causal drivers of this movement [2–4]. More recently, research effort has focused primarily on understanding the reasons for consistent intraspecific variation among individuals, investigating how morphological, behavioral, sexual, or age variation affect movement patterns [5–7]. Knowledge on the reasons and pattern of individual movements is especially im- portant in the management of pests, to ensure that pest control actions are undertaken at a scale relevant to the species. Knowledge on home-range size and use is critical, for instance, to determine number and density of traps, their placement, and timing of trapping operations [8–11]. The same scale problem is applicable to other control methods, such as contraceptives or poison baiting [12,13]. Simulation models to manage the population dynamics and spread of pest species also need estimates of home-range parameters [13,14]. Sex and age are two main individual causal drivers of variation in home range [7], and because of that, any pest control plan has to scale actions having taken into account these two key variables [14]. Psittaciformes (parrots) is one of the most endangered bird orders in the world [15], and, at the same time, this group also contains some of the most invasive and damaging alien species [16,17]. However, knowledge on movement patterns of parrot species, including invasive ones, is very limited. Current available information is based on the study of a few species and provides data on just a few radio-tagged individuals [18–22], which Diversity 2021, 13, 648. https://doi.org/10.3390/d13120648 https://www.mdpi.com/journal/diversity