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Raptor Nesting Season: How IRC Helps With Monitoring and Protecting Wildlife

Discover the wonders of springtime as Irvine Ranch Natural Landmarks welcomes new life! Learn about how IRC minors the success of the nesting season for the Orange County raptor population, including the popular red-tailed hawk 🦅🐣 #NestingSeason #RaptorMonitoring

Springtime is a season of new beginnings with many animals and birds having babies after the start of spring. Irvine Ranch Natural Landmarks is home to several species that welcome new additions during this time, making it an essential time to monitor their populations. One particular group that Irvine Ranch Conservancy (IRC) has been observing for nearly a decade is raptors, commonly known as birds of prey. The most common raptor species on the Landmarks is the Red-Tailed Hawk, making up a majority of the nests found during observation. Other common raptor nests found are Great Horned Owls, Barned Owls, Cooper’s Hawks and Red-Shouldered Hawks. 

Monitoring the nesting season of these birds serves two important purposes for IRC. Firstly, it allows them to identify areas with sensitive nests so that they can adjust their public activities accordingly and ensure we do not disturb them. Secondly, it allows them to track population trends over time, gaining valuable insights into the overall well-being of the raptor population. For instance, the White-Tailed Kite populations in Orange County have been declining since the early 2000s which has made them a high priority for nesting monitoring. Through observation this year, IRC has noticed the nests have a higher success rate than in years past, meaning a higher number of young raptors being produced.

Nesting season occurs annually within the Landmarks. Every year is a little different, emphasizing the need for monitoring to track trends. Interestingly, in recent years, the nesting season seems to have been shifting earlier, with nests being observed from February to early March. As a result, the season is expected to extend into May and June. While it is too early to tell definitive trends for the year, IRC has also noted a very productive year in terms of the nesting success, resulting in more young raptors. This could possibly be attributed to the increased rainfall over the past few years, as the rain increases the prey population that raptors rely on to feed themselves and their young.

Discover the wonders of springtime as Irvine Ranch Natural Landmarks welcomes new life! Learn about how IRC minors the success of the nesting season for the Orange County raptor population, including the popular red-tailed hawk 🦅🐣 #NestingSeason #RaptorMonitoring
Baby Barn Owls found on Irvine Ranch Natural Landmarks during nesting season.

To efficiently monitor these nests, IRC collaborates with two local professional biologists who divide the Landmarks into two sections: north and south. Pete Bloom from Bloom Biological Inc. oversees the North Ranch, while Scott Thomas from Kidd Biological leads the South Ranch. Once the nesting season begins, these experts visit on a monthly basis to monitor the nests, sharing their notes in a comprehensive database that tracks every nest discovered. Trained IRC volunteers contribute to the data collection by monitoring the nests weekly or bi-weekly, focusing on determining whether a nest is active or if it has failed.

As mentioned, the information obtained through this essential monitoring process allows IRC to implement necessary closures within specific sections of the Landmarks, ensuring humans do not disturb the nesting areas for these raptors. This might be why some of your activities were closed or rerouted. Closures are implemented in stages, with complete closures, followed by access only for IRC vehicles, quiet zones for the public and then a complete reopening. If you encounter a canceled activity or notice a quiet zone sign during your future hikes, it is likely due to nesting raptors nearby. Please remember to respect this delicate environment so both humans and animals can thrive harmoniously.