A Glimpse into the Monitoring of New Jersey’s American Kestrels

by Rachel McGovern, Communications and Outreach Manager

New Jersey is home to three native falcon species, the peregrine falcon, merlin, and American kestrel. Falcons are fierce predators known for their swift flight and intensity. Of these species, I am always most excited to spot an American kestrel.

These small falcons, roughly the size of a mourning dove, are the smallest falcon species in North America. They thrive in habitats with short vegetation such as parklands, meadows, and agricultural areas. Here, they hunt for insects and small animals like mice and voles. You can often see them perched on wires or branches, scanning for prey with their distinctive tail-bobbing behavior. They nest in tree cavities or specially placed nest boxes near fields and meadows.

Recently, I had the privilege to join New Jersey Fish & Wildlife’s (NJFW) Endangered and Nongame Species Program’s American kestrel monitoring team at a nestbox site to band young kestrels. The NJFW American kestrel project works with volunteers to monitor nest boxes in New Jersey and gather critical data about this species. American kestrels were designated as a State threatened species in 2012. While there is still a lot to learn about their decline, it is understood to be at least partially due to habitat loss and a lack of nesting sites. NJFW has been monitoring these small falcons to learn about their decline and support their recovery.

A band is placed on a kestrel’s leg. Photo courtesy of Steve Neumann.
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International Migratory Bird Day Series: American Kestrel

CWF is celebrating International Migratory Bird Day all Week Long

by Lindsay McNamara, Communications Manager

CWF’s blog on the American kestrel is the fifth in a series of five to be posted this week in celebration of International Migratory Bird Day (IMBD). IMBD 2016 is Saturday, May 14. This #birdyear, we are honoring 100 years of the Migratory Bird Treaty. This landmark treat has protected nearly all migratory bird species in the U.S. and Canada for the last century.

American Kestrel photo by Robert Lin.
American Kestrel photo by Robert Lin.

In New Jersey, catching a glimpse of an American kestrel is a rare treat! These beautiful, colorful birds of prey are about the size of a mourning dove — they are the smallest falcon in North America. Kestrels are one of two falcon species that nest in New Jersey.

 

American kestrels are opportunistic hunters, feeding on a number of different animals like grasshoppers, lizards, mice, snakes and small birds. Unlike peregrine falcons, kestrels don’t use speed to kill their prey. They perch to see their target and then use a stationary, hovering flight that allows them to dive down short distances to capture their prey. The eyespots of a kestrel make it appear to be “looking” up at its aerial predators, like Cooper’s hawks, causing the predators to move on to find a less “alert-looking” target. The eyespots give kestrels the opportunity to focus on hunting for prey beneath them.

 

Kestrels also hide surplus prey in grass clumps, tree roots, bushes, fence posts, tree limbs, and cavities, to save the food for lean times or to hide it from potential thieves!

 

Kestrels utilize these hunting tactics in open, grassy habitats — especially ones with cavities for nesting and perches for hunting. Kestrels can be seen hovering in grasslands, pastures and parklands or perched along the road on telephone lines.

 

KestrelRangeKestrels can be found in both North and South America, from Alaska and Canada in the north to Argentina in the south. During winter in North America, they will migrate southward from the northernmost portion of their range. They live year-round within New Jersey.

 

Although the American kestrel is widespread, meaning they live year round throughout much of the United States, the northeastern kestrel population is declining. Today, the kestrel is listed as a threatened species in New Jersey.

 

The decline of kestrels in New Jersey is likely due to destruction of grasslands from development. Nesting cavities are also being lost. As humans clean up fields, we remove trees with nest cavities that kestrels use. Kestrels are secondary cavity nesters. They don’t make their own cavity but use existing natural or man-made cavities.

 

Since kestrels nest in buildings and other man-made structures, nest box programs are an effective way to help grow the number of kestrels in areas where nest sites are limited.

 

Conserve Wildlife Foundation of New Jersey, in partnership with the Endangered and Nongame Species Program implemented a nest box installation and monitoring program in 2006. Nest boxes have been placed in areas of habitat determined to be suitable for the birds of prey. The boxes are monitored by biologists during the breeding season. Because kestrels reuse nest sites, particularly if they have successfully raised young, we focus on boxes that have been successful at least once since 2006.

 

The nest box program in New Jersey appears to be successful; we are adding to the population. Since 2006, we have banded over 300 fledglings. You can help too! Next time you see an American kestrel in the Garden State, be sure to submit a Rare Species Sighting form.

 

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Lindsay McNamara is the Communications Manager for Conserve Wildlife Foundation of New Jersey.