Common Nighthawks on the move

Nature Notes for August 29, 2014

“I saw a flock of birds flying over my yard, but I don’t know what they are. They are bigger than a swallow with a white blotch on each wing and their flight in like bats. Would you have any idea what they are?”

Several times in the past couple of weeks, I have received queries similar to the one above. I wish all bird identification questions were as easy as this one. The birds in question were Common Nighthawks. There have been a number of recent reports of migrating Common Nighthawks and I’ve seen them over my house in Port Hope.

Common Nighthawks aren’t hawks at all, but are part of a group known as nightjars. For reasons that no one really knows, this group is sometimes called goatsuckers. It was thought that they entered barns and sucked on the teats of goats. This is, of course, a myth, but the name has stuck.

They are aerial foragers which hunt for flying insects primarily at dawn and dusk. For the size of the bird, they have a very large mouth with rictal bristles. These are similar to the whiskers on a cat and, combined with the wide mouth, are very effective in scooping flying insects from the air.

The colouring of Common Nighthawks is a mottled mixture of shades of brown. Since they prefer to nest on the ground in open sites, this coloration provides good camouflage. The white spots on the wings aren’t visible when the bird is perched.

Their natural nesting habitat is in open areas, such as those provided after a forest fire, or on rocky outcrops in the Canadian shield. Their nests can be found in openings in the forest due to fires or clear cuts, on sandy blowouts and in old, unused gravel pits.

Since the mid-1800s, they have also been found nesting on flat gravel roofs in urban areas. This type of roof is no longer in favour with builders, so this habitat has reduced somewhat. Initially, the rooftop locations provided protection from predators such as foxes, raccoons and skunks. However, urban gulls and crows have discovered the nighthawk nests and are now major predators of roof-nesting nighthawks.

In the spring, Common Nighthawks are most often detected by sound. Their call is a loud “peent”. The males have a spectacular display flight. The will fly to a great height and plummet towards the ground and a waiting female. Just when it seems that they will crash, they pull up, which causes a loud booming sound from the wind forced through their wing feathers. This boom can be heard over quite a distance and has contributed to another colourful name for this species: Bullbat. Bull was because of the loud booming sound and bat because of the style of their flight.

As with all the aerial foragers, their populations are showing declines. In the twenty years between the two Ontario Breeding Bird Atlases, there was a significant decline in the observations of Common Nighthawk. They are listed as “Threatened” by the Committee on the Status of Wildlife in Canada (COSEWIC) and as of “Special Concern” by the Ontario Ministry of Natural Resources  (OMNR).

Their breeding range includes most of North American south of the tundra. The ones that are passing through Northumberland now are heading to wintering areas in South America, as far south as northern Argentina.

Probably by the end of this week, when this article appears in print, most of the Common Nighthawks will have moved through the area.

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Presqu’ile Provincial Park is holding the 30^th annual Monarchs and Migrants event over Labour Day weekend. Check the Friends of Presqu’ile web site http://www.friendsofpresquile.on.ca/ for the complete schedule of events. They include guided bird hikes, bird banding and Monarch butterfly tagging.

On September 20, Alderville Black Oak Savanna hosts Prairie Day, a project of the Rice Lake Plains Joint Initiative.

Local Birds Can Appear Exotic

Nature Notes for July 25, 2014

There was an audible gasp from all the members of the group as binoculars focused on the bird. It was a richly velvet black with red and yellow on its wings. What was this rare bird? Why a Red-wingedBlackbird, a common breeding species in our local marshes. The observers, however, were from Japan so this was a new bird for them.

It has been my pleasure and privilege recently to introduce my local birding patch to two groups, one from a great distance and one from further north in Ontario. Many bird species which are common here were new to both groups.

One of the reasons people like birds is for the beauty of their plumage. It is very easy, however, to think that one must go to an exotic location to see beautiful birds. If you really look at them, the regular inhabitants of many gardens are quite exotic.

Once at a bird banding demonstration in Presqu’ileProvincial Park, a member of the public asked the identity of that large black bird with all the colours on its head that was hanging around his campsite. As I asked additional questions about the bird, it was identified as a Common Grackle. This person had seen them before, but not really looked at the bird. There is an iridescent sheen of purple and green on the head of the males which is quite striking.

Another bird which delighted the Japanese visitors was a male Northern Cardinal. This bird is bright red with a black mask around the eyes. It was a visiting a feeder, so offered very good views. The male was accompanied by a female, too. She is more a buff colour with red highlights, more subtle, but still beautiful.

The other red bird seen locally is Scarlet Tanager. Males of this species are all red with black wings. This plumage only lasts through the breeding season. They arrive in this plumage in the spring, but after nesting molt to yellow with black wings, the plumage they hold for most of the year.

I never tire of the sight of male Rose-breasted Grosbeaks. They are black and white with a splash of red at the throat.

Although many woodpeckers have some red, the Red-headed Woodpecker is certainly the most striking. It has an all red head with large blocks of black and white on body and wings. In this species, both male and female have the same bright plumage. Sadly, this bird is in decline throughout most of its range. Northumberland County is fortunate enough to still have breeding Red-headed Woodpeckers.

A local breeder like this Yellow Warbler can seem quite exotic
 to those unfamiliar with the bird.

photo  © Rob Lonsberry

This spring and summer, several people have asked me the identity of a bird seen on the ground. It had some red on its head and a black V mark at the throat/upper breast. This bird turned out to be a common woodpecker, a Northern Flicker. Because they often eat ants, they can be found on the ground. In addition to the markings described, this bird has yellow wing linings and a white patch on the rump.

If Blue Jays were not so common, I expect that they would be considered quite exotic. There are several different shades of blue on their plumage from almost turquoise through sky blue to navy highlights. Mixed in with a black necklace and black and white spots on the wings and tail, it is quite striking.

There seem to be fewer blue birds in this part of the world than other colours, so they seem more exotic. I was able to show my groups two others. The male Indigo Bunting is iridescent blue all over. Because this colour is iridescent and not a pigment, in some lights the bird just looks dark. However, in the right light, the blue colour is amazingly bright.

The other local blue bird is actually called that: Eastern Bluebird. This one is a member of the thrush family. The male has a blue back and red breast the same colour as a robin’s breast. No doubt this colouring has encouraged many people to put us suitable nesting boxes for this species.

I haven’t even mentioned the orange and yellow birds such as Baltimore Oriole or Yellow Warbler. These, too, to unfamiliar eyes seem very exotic. Perhaps readers will take a closer look at some of our common birds.

Rice Lake Plains Butterfly Count 2014

Nature Notes for June 27, 2014

If, last Saturday, you encountered a group of people along a roadside staring at something invisible to the onlooker and laden with a butterfly net, you stumbled upon participants in the second official Rice Lake Plains Butterfly Count. Butterfly Count.  Regular readers will know about bird counts, but butterflies? This is another way that information about the natural world is collected.

Teams are assigned to a particular geographic area and fan out to try to find as many butterflies as they can. The ideal day is warm and sunny. Butterflies are not very active below a temperature of 20ºC.

The June 21 date was bit earlier than most butterfly counts in southern Ontario. The date was chosen to coincide with the flight season of the Mottled Duskywing, which has recently been listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

Each butterfly species has a particular flight season, some having more than one flight during the warm months. Some, like the Mourning Cloak, have a very long flight season. They overwinter as adults, emerge with the first warm weather, and can still be found into September. Others, like the Mottled Duskywing have a short flight season, about six weeks from mid-May through June.

The Mottled Duskywing is not a particularly striking butterfly. It is small and dark with various shades of brown splotching. It does, as do many butterfly species, have very particular habitat requirements. The only food of the larva (the caterpillar stage) is New Jersey Tea, a small flowering shrub of the dry prairie/savannah habitat of the Rice Lake Plains.

Most school children are familiar with the life cycle of the Monarch butterfly whose larvae feed only on milkweed. Many other butterfly species are just as particular. The Monarch mimic, the Viceroy larvae feed on willows and poplars. Red Admiral and Milbert’s Tortoiseshell larvae feed on stinging nettle. Baltimore Checkerspot feed on turtlehead (That is the name of a plant.) CommonBuckeye feeds on toadflax and snapdragon. Black Swallowtail feed on members of the parsley family, including garden carrots. Quite a number of species feed on a variety of grasses.

  One of many Northern Crescents seen on the count

photo © Rod Lee

Locating the larval food plants will indicate the likelihood of finding the butterfly at the right flight season.

The adult butterflies are often found nectaring on flowers. Last weekend was a bit early for too many flowers to be in bloom, but roadside patches of vetch and viper’s bugloss usually yielded a few butterflies. Often, butterflies are found on patches of damp ground where they suck up dissolved minerals. Another place to look for them is on animal scat. This doesn’t provide the most picturesque background, but the butterflies also obtain nutrients for this source.

How did we do on the count? The group’s tally was 39 species. Five Mottled Duskywings were seen. The most abundant species was Common Ringlet, with 327 individuals seen.

 Common Ringlet, the most abundant of the butterflies seen on this count.

photo © Rod Lee

Only two Monarchs were seen by the group. This species should have arrived back from Mexico by this date. Only time will tell whether this species’ eastern population will survive.

Perhaps some readers will study their butterflies over the summer so that they might take part in the 2015 Rice Lake Plains Butterfly Count, scheduled for June 2015. The count was sponsored by the Rice Lake Plains Joint Initiative and organized by the Peterborough Office of the Nature Conservancy of Canada.

Thousands of Dunlin visit Cobourg Harbour

Nature Notes for May 30, 2014

“Want to see a couple thousand Dunlin?” My husband greeted me with this question when he came in from work last Monday evening.

“Where?” I responded.

“Cobourg Harbour” he replied, “but there are none in Port Hope. I checked.”

Off we went to Cobourg. Away from the Atlantic coast, I don’t think that I have ever seen so many shorebirds. They lined the sand beach on the west side of the harbour, perched on the rocks of the breakwater and fed in several large flocks on the surrounding lawns. All were feeding furiously on midges. Joggers and walkers didn’t seem to bother them. They would fly up, wheel around and then settle back to eating. If one stood still, they would approach your feet.

Some of the thousands of Dunlin that visited Cobourg Harbour last weekend.

Photo © Rob Lonsberry

Dunlins are medium sized shorebirds. In breeding plumage, which they are wearing now, they have a gray face, rust coloured back and a large black patch on the belly. They have a relatively long bill, black and with a slight droop at the tip.

Close up of a single Dunlin

Photo © Rob Lonsberry

As with many shorebirds, it is necessary to learn them in several plumages. The juveniles are different from the breeding adults, which are different than the non-breeding adults. The same Dunlin migrating back south in early summer will look quite different than the ones seen this week in Cobourg Harbour.

Dunlins are a circumpolar species, occurring in Europe and Asia as well as in North America. The birds that were visiting Cobourg are probably the population that winters from the mid-Atlantic states in the U.S. to the Gulf of Mexico. This is further north than many shorebirds. Many other shorebirds travel to South America for the winter months.

These birds are en route to the tundra, where they will nest. The abundance of insects there provides lots of food on which to raise the young. Dunlins eat mostly insects, although they also feed on aquatic invertebrates.

The big flocks of Dunlin were first reported in Cobourg Harbour on Sunday, May 25. On that date, they were accompanied by a single Red-necked Phalarope, one Whimbrel, and a few each of Short-billed Dowitchers, Red Knot, Ruddy Turnstone, Sanderling and some “peeps”. Most of the latter were Semipalmated Sandpipers, although there was one Baird’s Sandpiper, a very unusual bird for the spring in Ontario.

On Monday, there were still about 2000 Dunlin, many Ruddy Turnstones, many Semipalmated Sandpipers and a few Whimbrel and Red Knots.

The birds came and went throughout the day. On several visits throughout a day, the mix of species could be quite different, although this week they were dominated by Dunlin.

Before we left Cobourg Harbour, several Dunlin flocks lifted off and headed north. We didn’t visit on Tuesday, but probably there were very few shorebirds left. Why they chose to visit Cobourg this week is a mystery. We could only enjoy the sight.