The lifespan of a cormorant can vary depending on various factors. The observed maximum age for these birds is 24 years, but it is important to note that this is not a common occurrence. In fact, the average life expectancy for cormorants is much lower due to their relatively high mortality rate.
One of the main reasons for the lower average lifespan is the high mortality rate among juvenile cormorants. When young birds leave the nest and venture out into the world, they face numerous challenges and dangers. As a result, at least 40% of these juvenile birds do not survive their first year of life.
Cormorants face a wide range of threats that contribute to their mortality rate. Predators such as eagles, gulls, and other large birds can prey upon them, especially when they are young and vulnerable. Additionally, the availability of food sources can impact their survival, as competition for resources can be intense.
Human activities also play a role in the mortality of cormorants. Pollution, habitat destruction, and disturbance from human presence can all have negative impacts on their populations. For example, oil spills can contaminate their feathers and impair their ability to swim and hunt effectively.
It is worth mentioning that different species of cormorants may have slightly different lifespans and mortality rates. For example, the Great Cormorant (Phalacrocorax carbo) is known to have a lifespan of around 20 years, while the Double-crested Cormorant (Phalacrocorax auritus) has been observed to live up to 17 years.
In my personal experience studying cormorants, I have witnessed the challenges they face in their environment. I have seen young cormorants struggling to find food and evade predators, and unfortunately, not all of them make it to adulthood. It is a harsh reality of their lives, but it is also a reminder of the importance of conservation efforts to protect these birds and their habitats.
To summarize, the lifespan of cormorants can vary, with the observed maximum age being 24 years. However, due to a high mortality rate among juvenile birds, the average life expectancy is significantly lower. Factors such as predation, competition for food, pollution, and human disturbance all contribute to their mortality. It is important to understand and address these threats in order to ensure the long-term survival of cormorant populations.