10/14/2024 - American Golden Plover or Black-bellied Plover

     Last Thursday I drove the beach at Island Beach State Park hoping to pick up a few fall birds that might be passing through the area, particularly an American golden-plover.  AG plovers (for short) are considered rare for us here in New Jersey, but fall is the best time to find one since their return migration route usually takes them down the eastern coast.  The northbound migration route for these arctic breeders is across the central United States, making them an even rarer find in the spring.  I have been successful the past years finding at least one AG plover by traveling the beach in September and October and scanning flocks of black-bellied plovers.  AG plovers usually associate with the more common and similarly looking black-bellied plovers (BB plovers, for short).

The first plover I came upon yesterday was by itself, and it immediately caught my attention.  My first take was that this is a good candidate for an AG plover.  BB plovers and AG plovers look very similar in both their breeding and nonbreeding plumages.  For many birders it is probably easier to spot the difference when both birds are next to each other.  When standing together, it is easier to notice the smaller AG plover with its more rounded head and more delicate bill.  However, when there are dozens of plovers huddled together, or running around on the beach, it can still be difficult to find the different one.  I'll share some physical comparisons of BB plovers and AG plovers I have documented over the past few years to help make identification a little easier.  Of course, vocalizations are helpful identifiers but are not included here.  (AG plovers and Pacific golden-plovers were once considered the same species and separating these two is even more difficult.  I am excluding the latter here because there are only three records of PC plover in New Jersey.)

AG plover at Island Beach State Park (IBSP), 10/10/2024.  © S. Weiss

The bird pictured on the left above shows a rounded head and a smaller, thinner bill than what a black-bellied plover would have.  The photo on the right shows the diagnostic pale coloring at the armpit area of the underwings.  The AG plover's armpits are pale in all plumages.  A BB plover would have dark armpits.

Left, BB plover at IBSP, 5/18/2020.  Right, BB plover at IBSP, 9/5/2024.  © S. Weiss

The birds pictured above are in mostly breeding/alternate plumage.  The black on their bellies extends to just about their legs.  The black armpits are clearly visible when in flight.

BB plover (on top) and red knot (on bottom) at IBSP, 11/2/2022.  © S. Weiss

The BB plover in the above photo is in basic/nonbreeding plumage and the diagnostic black armpit is visible.  The black armpit is present in both basic and alternate plumages.

AG plover at IBSP, 9/13/2024.  © S. Weiss

The AG plover pictured above is still mostly in alternate plumage.  The black under its belly extends beyond its legs to the undertail coverts.  Compare this to the BB plover above.

Left, AG plover and BB plover at IBSP, 10/9/2017.  AG plover and BB plovers at IBSP, 10/16/2019.  © S. Weiss

The pictures above give side by side comparisons of AG plover and BB plover.  Without seeing the diagnostic armpits, other differences between the species can be seen.  The AG plover is overall slightly smaller and more slender in appearance.  It has a smaller head and a shorter, thinner bill.

BB plover at IBSP, 10/10/2024.  © S. Weiss

The BB plover pictured above looks striking similar to the AG plover at the top of the page.  Both were lone plovers with golden colored backs.  This one looks a little chunky and its bill looks kind of stout.  When this bird took flight, its black armpits stood out, cinching its identification.

AG plovers at IBSP.  Left, 10/6/2021; Right, 10/13/2022. © S. Weiss

There are no black armpits on the birds pictured above.  Quite simply, they are AG plovers.

BB plovers at IBSP, 11/3/2022.  © S. Weiss

Those shorebirds flying in the distance out over the ocean have black armpits, so they are BB plovers.

Separating AG plover from BB plover is not too hard when you know their differences.  Just keep in mind, that NJ has two records of European golden-plover and three records of Pacific golden-plover which look very similar to AG plover.  You never know what might show up.









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