A MICE approach to scoping the possible impact of guano harvests on trends in penguin abundance

A simple population dynamics model is used the scope the possible impact of guano harvesting during the 20th century on penguin population trends, as a consequence of the associated reduction in optimal breeding habitat diminishing reproductive success. The analyses’ outputs include the delays arising from transient effects. They indicate that guano harvesting (which ended in 1992) could have been a major contributing factor to the reduction in penguin abundance over the last few decades of the 20th century. However, transient effects become minimal after the turn of the that century; such effects could not (even partially) account for the decline in penguin counts after about 2015.