Yowza

Introduction

Long distance migration is a life history strategy employed by a wide range of species. Migration is exhibited by mammals, fish, birds, insects, reptiles, and marine invertebrates. One of the most important environmental factors promoting long distance migration is seasonal variability in the availability of resources. Reproduction is another common reason for the need of some species to migrate; for example, it may be more suitable for eggs to be laid or young to be born in areas with reduced predation (Alerstam et al. 2003). Often -- especially with travel over vast distances -- the energy cost and associated mortality risk of migration are considerable (Wikelski et al. 2003). This cost must be outweighed by the fitness benefit conferred by making the trip, and as a result, many species have physiological methods of assessing the environment to determine the suitability of embarking at a given time. Some of these methods include responding to changes in photoperiod, temperature, or internal fat reserves. Adaptations for navigational purposes are also required, including: using the sun or stars as compasses; detecting polarised light; responding to olfactory cues; and detecting magnetic fields (Alerstam et al. 2003). These environmental cues and navigational adaptations are necessary for the successful migration -- and therefore survival and reproduction-- of a wide variety of ecologically significant species. In modern times, development by humans can often impede the travel of migratory species. Also, some technology utilized by mankind can interfere with the aforementioned navigational adaptations (Arnett et al. 2008). Thus, I propose that when species' migratory paths or destinations overlap areas of major human development migration is less successful than when little or no overlap occurs.

Substance

I plan on expanding on all areas touched upon in the introduction, in the same order:

• Provide examples of species that migrate in search...