Photo of the Week

This photo shows butterflies puddling on a pile of scat at Negri-Nepote Native Grassland Preserve. Puddling is a common behavior among butterflies. While butterflies can supply their energy needs by sipping nectar at flowers, they must look elsewhere for other nutrients like minerals. Sometimes they do this in actual puddles or muddy patches, but they will just as readily feed from scat. In this case, it provided me with a butterfly lifer, a Hackberry Emperor. The Hackberry Emperor is one of several butterfly species that begins its life cycle on the leaves of hackberry trees, particularly American Hackberry. Other hackberry specialists include American Snout, which I have seen during past vists to Negri-Nepote, and Tawny Emperor.

Photos of the Week

This weekend I participated in the Union County BioBlitz, which covered a cluster of three small suburban parks: Nomahegan, Lenape and Echo Lake Parks. The parks follow the course of the Rahway River and one of its tributaries. The habitats are mostly riparian woodland, with some open fields (both mown and unmown) and freshwater ponds. Saturday was my first time attending this event, but it has been held every year since 2005 and rotates among parks in Union County. A bioblitz is similar to a big day in its duration, but all taxa are eligible and the idea is to make as complete a census as possible of the living things at a particular site. Teams cooperate and share information, and there is usually an educational component.

The bird team came up with 70 species, which is very good for Central Jersey in June. Their sightings included a lingering Magnolia Warbler (which I missed). I came up with a little more than half that, but I was primarily working on insects. I am still sorting through my insect photos to identify and post them. So far I have 27 insect species on my list, with a lot more to identify. I know the total insect list from bioblitz will run into the hundreds.

My weekend included two lepidopteran lifers. One is the Banded Hairstreak shown above; the other is the Eight-spotted Forester shown below. Banded Hairstreak uses oaks, walnuts, and hickories as larval hosts and flies in late spring and summer. Eight-spotted Forester is hosted on vines, particularly grapes and Virginia creeper. While butterflies and moths feed on plants during their larval stages, as adults they drink nectar from flowers, and in the process pollinate many plants, which is necessary for the plants to reproduce. Both of these are fairly common species, so the fact that I had not seen either yet might seem surprising. However, insect lives are very short, and few of them migrate. Many butterflies and moths only fly for a few weeks, so if you are not in the right habitat at the right time, you will probably not see them.

If you would like to learn more about the moth diversity in your area, consider participating in National Moth Week, which is coming up very soon. This year the event runs from July 20-28.  Visit the link to learn more about how to participate.

Photo of the Week: Summer Azure

Birders recognize the transition from Yellow-rumped Warblers to Blackpoll Warblers as a sign that spring migration is reaching its final stages. The situation is more complex than that, as both species are present together for two or more weeks. But if you hear Blackpoll Warblers but not Yellow-rumped Warblers, you are probably in the last week or two of May.

In the same way, one can find seasonal harbingers elsewhere in the natural world. One of them is this species, Summer Azure, which shows up around the same time that Blackpoll Warblers are leaving. Summer Azure is part of a species complex that used to be known as "Spring Azure." Thanks to careful study of phenology, genetics, and microscopic traits, what once was one species is now several species, with a succession of overlapping flight seasons, starting in early spring and continuing through summer. Summer Azure is the last to appear and has two broods. In New Jersey the first emerges in late May or early June, and the second emerges later in the summer.

I photographed this Summer Azure in the Rutgers Ecological Preserve last week.

Mapleton Preserve

Back at the beginning of May, I birded at Heathcote Meadows, a county-owned preserve in South Brunswick Township. Heathcote Meadows is part of a greenbelt around Kingston that links it with the Delaware and Raritan Canal State Park, the Mapleton Preserve, and Cook Natural Area. Yesterday I birded Mapleton Preserve, which is part of a former plant nursery. A lot of the nursery buildings still exist, and the grounds are a mix of meadows with hedgerows in between them. This sort of habitat can be very productive for birding, and so it was yesterday, even with a late start.

I saw or heard at least six Field Sparrows, including one obvious pair. One male Common Yellowthroat was carrying a fat green caterpillar that looked as big as its head. Several Indigo Buntings were present and singing in the fields. A Willow Flycatcher was a pleasant surprise – perhaps it is more common in Middlesex County than I thought. Even better was a White-eyed Vireo singing near a pipeline cut that runs adjacent to the preserve. Along the same pipeline cut were a singing Prairie Warbler and an Orchard Oriole.

There were some butterflies active as well. The one above is a Question Mark in its winter form, which has orange hindwings and frosted edges.

At least 15-20 Cabbage Whites were clustered around a single mud puddle along the pipeline cut. Here are five of them.

Several Little Wood Satyrs were flying on a shaded trail.

As one would expect, a lot of Eastern Tailed-Blues were active in the fields. This one was cooperative.

Juvenal's Duskywing

Duskywings are a difficult group of butterflies to sort from each other. Duskywings belong to the family Hesperiidae, i.e., the skippers. Unlike typical skippers they hold their wings spread out at rest (as opposed to the jet plane posture). As the name indicates, duskywings are dull brown, and they have remarkably similar wing markings. Two things point to this being a Juvenal's Duskywing, however. First, the pattern of small white spots, especially on the undersides of the wings, is closer to what would be expected of a Juvenal's Duskywing than similar species. Second, the uppersides of the wings are covered with fine white hairlike scales, a trait that is not true of the very similar Hoarce's Duskywing. In its larval form, this species feeds on oaks. This individual was sipping moisture or minerals at a mud puddle.

Eastern Tailed-blue at Griggstown Grasslands

While Eastern Tailed-blue is one of the most common species in my area, it can be a frustrating butterfly to photograph. These butterflies are tiny, which necessitates a very close approach, but they are skittish enough that a close approach is likely to make them take flight. When they do sit, the usually keep their wings folded over their backs, so that the light gray undersides are visible instead of the brilliant blue uppersides.

So yesterday, I was very happy to find some cooperative Eastern Tailed-blues at Griggstown Grasslands. Perhaps the cooler weather had something to do with it, as these individuals preferred to bask in the sun with their wings open. Maybe they reacted a little more slowly to my approach due to the morning chill. Whatever the reason, these butterflies were a treat.

Eastern Pine Elfin

Yesterday at the Phillips Open Space Preserve in Old Bridge, I came across this butterfly fluttering around near the ground. It turned out to be one I had never seen before, Eastern Pine Elfin (Callophrys niphon). It was not very cooperative, so I did not get as clear or as close of an image as I would have liked. There was also a second, similarly-sized butterfly that was likewise unfamiliar, but I never managed to get a photo of it, so I am still not sure what it was.

Elfins are in the family Lycaenidae, along with coppers, hairstreaks, and blues. I think of them as specialized hairstreaks. In fact, they share the genus Callophrys with the green hairstreaks like Juniper Hairstreak. Elfins fly in early spring; in New Jersey this means flight periods ranging from late March through early June.

According to Gochfeld and Burger's Butterflies of New Jersey, Eastern Pine Elfin is common in the Pine Barrens in April and May. The Phillips Preserve is one of the northernmost remnants of Pine Barrens habitat in New Jersey, so it was in appropriate habitat. After mating, female elfins lay their eggs on the new growth of coniferous trees, especially Scrub and Pitch Pine.

Orange Sulphur

Prompted by the exceptionally warm weather, butterflies emerged in a big way this week. Just in the last two days, I have seen my first Cabbage White, Orange Sulphur, and Mourning Cloak of the year. Above is an Orange Sulphur sipping from a Lesser Celandine flower in Donaldson Park yesterday afternoon.

Red Maples are among the many plants blooming right now.

Monarch on Buddleja

Monarchs are still present in good numbers. I have not seen a repeat of the numbers that occasioned my monarch migration post. However, they are still present in higher numbers than I would see during the summer, so presumably their number is being swelled by southbound migrants. If you want to see migrating monarchs, now is the time to do it, before the cold sets in.

Early Autumn Butterflies

While many butterflies are already past their flight periods, some are still flying in good numbers. There are, of course, Monarchs that have been migrating through in a steady stream. However, they are not the only ones present.

Late summer and early autumn seems to be the prime season of Common Buckeyes in New Jersey. They are present for most of the warmer months, but I usually do not see them in such numbers as in early October.

Common Buckeyes are easily recognized by their eyespots and the white and red markings along the leading edge of the forewing.

Other butterflies that fly throughout the summer are also present, like this Orange Sulphur.

Early autumn is also a good time to spot southern butterflies that have strayed north. A regular southern visitor to New Jersey is the Fiery Skipper. The primary range of this species is in the southeast, but it wanders north from August to October.

Silver-spotted Skipper

There were fewer Monarchs around this afternoon than there were yesterday, but there were still several of them working the butterfly bush outside my window. Among them was this Silver-spotted Skipper. This is one of the larger skippers. Unlike most skippers, this one is easily recognizable because of its tall shape and the white splotch on the underside of its hindwing. It usually sits with its wings folded over its back instead of using the jet plane posture of the smaller skippers. Very occasionally I have a Silver-spotted Skipper with its wings spread flat. Silver-spotted Skippers are very common, and their larvae feed on locusts, wisteria, and legumes.

Monarch Migration

There is a large butterfly bush with white flowers outside my window. On most days I see a few butterflies at it, and some days there are a lot, with multiple species visiting it. Yesterday, this bush was covered with Monarchs. I could see at least a dozen at a time, and I could tell that more were present because I cannot see the entire bush from one position, and Monarchs kept arriving and leaving. Normally there will only be one or two Monarchs among the butterflies at the bush, so I think there must have been a major migratory movement yesterday.

Monarchs are probably the most familiar insects to the general public, as they are often used in schools as examples of biological phenomena like metamorphosis and mimicry. They are also large, colorful, and (at times) plentiful, so they are easily noticed even by people whose eyes are not tuned to insect movements.

Unlike most butterflies, Monarchs are fully migratory. In the fall, the eastern population migrates to wintering grounds in central and southern Mexico, while the western population retreats to southern California. In spring, these routes are reversed. No individual Monarch completes the entire round trip. Rather, females from the wintering population lay eggs in February or March, and subsequent generations complete the northward journey.

As with birds, geography influences Monarch migration. The best places to see large numbers of Monarchs at once are at southward-pointing peninsulas, like Cape May Point in New Jersey. Sometimes the air will be so full of Monarchs (and dragonflies!) that it can be hard to pick out birds from other flying things. One of my most memorable experiences of Monarchs was at Point Lookout State Park in Maryland on a chilly October morning when thousands of Monarchs were gathered at the point of the peninsula as they waited to warm enough to continue their journey. Migration occurs across a broad front, however, so you may see increased numbers in other butterfly gardens as Monarchs migrate.

Least Skipper

I found this Least Skipper on my local patch yesterday afternoon. I accidentally flushed it off of some asters, but it landed nearby. It then sat very still while I took a series of photos of it. I almost turned my ankle while I was getting into position to photograph it because a deep rut hidden in the long grass. As you can guess from the name, Least Skipper is a tiny butterfly. It prefers wet meadows, marshes, and streams.

Butterflies and a Moth at Cold Brook Preserve

Until Saturday, I had never visited Cold Brook Reserve, a small wildlife area in northern Hunterdon County. It has a reputation as one of the best places in northern New Jersey to look for sparrows and other open-country birds, particularly during autumn migration after the preserve's fields have been harvested. On Saturday the sparrow numbers were not very high yet, though I did see individual Song, Chipping, and Field Sparrows. However, I did see a Bobolink fly over one of the fields, and there were a few hatch-year Indigo Buntings around.

While there were not a lot of sparrows, there were a lot of butterflies around. Among the most common were sulphurs. An Orange Sulphur is above; the orange color is only obvious on the tops of the wings.

I was delighted to see a Common Checkered-Skipper, which has a beautifully intricate pattern on its wings.

Another skipper at the refuge was this Dun Skipper, which I found in the brushy edge bordering the stream that flows through the refuge.

A lot of Eastern Tailed-Blues were fluttering around in the grass. These small blue butterflies have tails and hindwing spots that give the appearance of an additional face at the back of the butterfly. It is thought that these might fool predators about which end is the true head.

It is often difficult to get a good look at the uppersides of an Eastern Tailed-Blue's wings, but one individual sat with its wings open for a long time. In contrast of its light undersides, the upperwings are a dark bluish-black.

Finally, I also saw a few small moths flutter in and out of the grassy trail. Most were crambid snout moths, but one of them was this lovely Chickweed Geometer.

Backyard Butterflies

One advantage of having a lot of native plants in the backyard is that those plants tend to attract a lot of butterflies and moths. Some come looking for a nectar source; others want to find good host plants for laying eggs. In my backyard, I have recorded over 20 species of butterflies (and many more moths). Some of them were probably just passing through (especially the Monarchs), but others are probably hosted here.

This Red Admiral was sunning itself on a grape leaf yesterday evening.

It was soon joined at its sunny perch by an Eastern Comma.

The two butterflies circled around each other a few times at first, but both soon settled down on nearby grape leaves.

A Spicebush Swallowtail was also patrolling in the area of the grape vines, and it landed in the grass a few times.

Red-banded Hairstreak

I found this Red-banded Hairstreak sipping nectar at one of the coneflowers in the backyard yesterday. It is at least the third year that this species has appeared in the yard. They show up sometime in July and appear in ones and twos for the rest of the summer. Red-banded Hairstreak have undergone a steady northward range expansion. Half a century ago, this species was rare in New Jersey; according to Gochfeld and Burger's Butterflies of New Jersey, there was only one record before 1940 and scattered records after that. However, in the last few decades, it has invaded the state and become rather common.

Insects at Willowwood Arboretum

Yesterday I was at Willowwood Arboretum in southern Morris County. In addition to the formal mansion garden and a Japanese garden, the arboretum holds several acres of meadow habitat bordered by small patches of woodland. This makes the property an excellent place to look for insects, particularly in July and August when insect diversity is at its peak.

Overall, I recorded 17 species of butterflies in Willowwood's fields yesterday. Many were common butterflies, like this Red-spotted Purple. Red-spotted Purple is actually a subspecies, Limenitis arthemis astyanax, and shares the species designation with White Admiral, Limenitis arthemis arthemis. White Admiral tends to be more northerly than Red-spotted Purple, though both subspecies can be found in northeastern states.

Other common butterflies included this Great Spangled Fritillary, Monarchs, Common Wood Nymphs, and Pearl Crescents. The latter two were by far the most abundant butterflies I encountered yesterday. Strangely, I did not see any of the less common browns.

This American Copper was one of the less common species I observed. This species is widespread, but apparently its abundance is highly localized. It is also tiny, which makes it even easier to miss.

The meadows tend to be fairly dry, so the arboretum is not as rich in odonates as a wetter habitat would be. Still it is possible to see some pretty attractive species there. Above is my favorite dragonfly, the Twelve-spotted Skimmer. A lot of the dragonflies in the meadows cruise around fairly high off the ground, which makes them hard to photograph, and sometimes even hard to see.

Another of my favorite odes is the Ebony Jewelwing, a stunning metallic green damselfly with black wings. A few of these were active along the bank of a stream that borders one of the meadows.

Butterflies and Dragonflies at Scherman Hoffman

Yesterday I was at Scherman Hoffman Wildlife Sanctuary, a nature refuge run by New Jersey Audubon in Bernardsville, to see what sorts of wildlife would be active there in midsummer. Most birds are well into their breeding season, but many were still singing. I was delighted to hear several singing Veeries; as I have noted before on this blog, the Veery's song is one of my favorites. Other singers included Wood Thrush, Indigo Bunting, House Wren, Chipping Sparrow, Ovenbird, and Common Yellowthroat. Some birds were clearly tending young already. I saw one House Wren perched in the entrance of a nest box (with another singing nearby) and a Black-capped Chickadee carrying a caterpillar, presumably to its nest site.

Despite the bird activity, I was more drawn to the insect activity yesterday. I had hoped that I might find a Harvester, an uncommon butterfly in New Jersey that is known to occur regularly at that preserve's beech groves, but I did not spot any. In addition to being a very attractive butterfly, it is North America's only predatory butterfly species: Harvester caterpillars prey on Woolly Aphids. Instead, I was treated to an array of other invertebrates. Great Spangled Fritillaries, like the one above, were active in great numbers; at one point I had six in one binocular field.

After seeing my life Delaware Skipper last week, I got to see another one this week.

I am pretty sure that this Northern Broken-Dash was a lifer; my butterfly records from past years are not thorough enough to be certain, but I have no recollection of seeing one before. This small, dark skipper could easily have passed unnoticed.

Dragonflies were active too, particularly in the area around a vernal pool close to the road. The dragonfly above is a Blue Dasher, one of the most common dragonflies in the area. This individual confused me at first since it was not holding its wings in the characteristic Blue Dasher posture.

Finally, this Spangled Skimmer was a dragonfly lifer for me. There were several of them perched among the cattails, some more worn than others. Above is a fresher individual, and below is a more worn one.