Crow Communication

American Crow on Feeding Platform

The American Crow (Corvus brachyrhynchos) is an interesting species.  It has abilities that are surprising.  Many studies have been done but some of their behaviour is still unexplained.  The following was observed by me recently.

Crow Communication

On the early morning of July 27, 2020 I was listening to the local crows communicating.  A single crow near our house was calling and being answered by a more distant crow. The local crow ‘cawed’ 4 times and was immediately answered by the more distant crow with 4 'caws' . The local crow then cawed 5 times and was answered by the more distant crow 5 times. That pattern repeated; local crow 6 times and answered with 6 caws; local crow 7 caws and answered with 7 caws. That went on in order through 8 and 9 caws. After a brief rest the local crow started again with 6 caws and was immediately answered with 6 caws. Next, 7 caws to be answered with 7 caws. This pattern continued through 8, 9, 10 and 11 caws. The answering crow did not make any mistakes until it got to 10 where it paused slightly, dividing the answer into 2 groups.  At 11, mistakes were made and the answering crow replied hesitantly with only 9 caws at which point the local crow ceased the exercise.

I was amazed by this display of repetitive behaviour and also by the ability of the local crow to keep increasing its delivery by one caw. I wonder if the local crow was an adult and the answering crow a juvenile or perhaps a mate. I would love to know more about crow communication and their behaviour. Crows truly are amazing.

American Crows Waiting for 'Breakfast' (Feeder) on a Wintery Morning

Pied-billed Grebe

Pied-billed Grebe [Internet Photo]

The Pied-billed Grebe (Podilymbus podiceps) is our smallest grebe.  Grebes are classed in the Podicipedidae family.  All members have lobed toes.  They build nests of matted vegetation on the ponds and lakes on which they live.  There are 7 species in 4 genera of the grebe family of which we normally have 3 species here in New Brunswick; Horned Grebe, Red-necked Grebe and Pied-billed Grebe.  The former 2 species are seen on salt water and Pied-billed Grebe prefers fresh water.  When the young of grebes are hatched, they are striped, very distinctive looking.

The Pied-billed Grebe is about 32 cm (13 inches) long.  It appears very small among the reeds and grasses of the ponds on which it lives.  This grebe is a fairly common summer resident here.  It is stocky in appearance and has brown upper parts with barred sides and flanks.  It has distinctive white undertail coverts.  The chin is black and the white bill has a distinctive black ring.  The bill is thick and the head appears large.  Both adult genders look the same.  In winter the adults lose the ring on the bill.  See photo below showing the ring beginning to fade.

Pied-billed Grebe 

 

The voice of this grebe is remarkable. They make a lot of noise for the size of them.  The long call is described in National Geographic Complete Birds of North America as, "a series of slightly hollow, rapid-paced cooing notes run into slower-paced, gulping clucks that can fade away or run on into more prolonged variations".  That sound is characteristic of many of our marshes.  When one learns that it is made by this small grebe, it is not forgotten.  The Pied-billed Grebe spends its summers in most of southern Canada and the northern US.  It winters in southern and central US, Mexico and the West Indies.  

The floating nest of this species is well-hidden and made of dead vegetation anchored to emergent plants.  The 2 to 10 light blue eggs are incubated for 23 to 27 days by both adults.  They eat fish, crustaceans, beetles, dragonfly nymphs and aquatic insects.  They forage by diving and collect their food usually underwater.  

Pied-billed Grebe Showing Young [Internet Photo]

The Pied-billed Grebe rarely flies when encountered, preferring to hide in the vegetation.  It has the unique feature of being able to submerge itself so just the head is showing.  This makes it nearly impossible to see.  Folk names for this species are interesting: dabchick, devil-diver, dive-dapper, hell-diver and water witch.  I have heard it called hell-diver by duck hunters who spend time on marshes.  

This neat little grebe is fun to watch and should be fairly easy to spot in New Brunswick in the summer.  A good place to see them is from the boardwalk at the Ducks Unlimited Marsh in Sackville.

Blackburnian Warbler

Blackburnian Warbler [Internet Photo]

The Blackburnian Warbler (Dendroica fusca) may be our most beautiful bird. The male in breeding plumage is breath-takingly beautiful. The mix of oranges, yellow, white, gray and black are masterfully arranged. It is unmistakable with its flaming-orange throat. The female is much drabber and can be distinguished from other warblers by her dark cheek patch which is surrounded by yellow. She also has a yellow incomplete eyering and pale stripes on the back. The juvenile is similar to the female.


There aren’t many warbler species one would mistake for the Blackburnian. The immature female Cerulean Warbler is similar but almost never found in New Brunswick. In the fall it may be confused with the Bay-breasted and the Blackpoll Warblers but they do not have the stripes on the back and they do show a supercilium (line over the eye).

Blackburnian Warbler [Internet Photo] 

We are lucky to be part of the Blackburnian Warbler breeding range. They spend their summers throughout eastern Canada from the central areas of Saskatchewan and Manitoba eastward to the Maritime Provinces. In the fall they take an easterly route through the eastern part of the US to their wintering grounds in mountainous forested areas of the northern Andes, the Amazon and northern South America. In the spring they return by a more westerly route up the central flyway. Their preferred habitats are mixed forests of hemlock, spruce and hardwoods. They are very useful birds in keeping our forests healthy. They eat caterpillars and beetles and other insects.


Blackburnian Warblers nest high (up to 30 m/85 ft) in a conifer tree, usually building their nest way out on the branch. The nest is made of twigs and lined with lichens, moss and hair. The 4 to 7 brown spotted white or pale green eggs are incubated for 11 to 12 days by the female.


The song of this species is very high-pitched and not able to be heard by some people. It is an ascending series on notes ending with a trill. It can be described as 'see see see see ti ti ti siii’.

Blackburnian Warbler [Internet Photo] 

The Blackburnian Warbler among other species is very important in controlling insect damage to our forests, e.g., the Spruce budworm outbreak. This small species is an important part of the forest ecosystem.

The Blackburnian Warbler was named after an English botanist, Anna Blackburne. It is unusual for a species to named after a woman. Also interesting about this species is the advantage it has because it builds its nest and often feeds very high up in the forest canopy. This protects the nest from parasitism by the Cowbird which lays its eggs in other species nests. The lofty habitat also gives it access to more insects which birds which feed lower do not get. 

 
Hemlocks are the favourite tree species for feeding and nesting for this species. Our hemlocks are large and healthy so the Blackburnian Warblers are doing well here.

Purple Martin

Purple Martins on Martin House

The Purple Martin (Progne subis) is a member of the Hirundinidae family.   It is our largest swallow.  In flight it appears long-winged.  The adult male is a uniform glossy blue-black.  The adult female and juvenile are more grayish.  All plumages show dark above with dark head and breast (although grayish in female and juvenile).  In flight the underwing coverts are very dark and the tail is forked.  The photo above shows a male on the top row and a female or juvenile peeking out of the bottom row.  

The Purple Martin is 18 cm (7.5 inches) long and has a wingspan of 45 cm (18 inches).  The male, to the untrained eye, could be confused with a Starling but the shape and bill length is quite different.  In some geographical areas it could be confused with other martin species but we have only the Purple Martin here in New Brunswick.  

Martins are very vocal frequently making a chur sound.  Their song is a series of chortles and gurgles.  The range of this species is widespread in North America.  They breed in most of the eastern half of southern Canada and all of the eastern US.  They also breed in isolated pockets of the western US and also along the west coast.  In New Brunswick Purple Martins are not common but are fairly common locally along the St. John River and other parts of southern NB, especially where martin houses are provided.  Cold, wet springs can be hard on them and competition for housing with Starlings and Tree Swallows can lead to a decline in local populations.  Purple Martins lay 3 to 8 white eggs.  Their nests are lined with mud and plant material.  The eggs are incubated 15 to 18 days by the female.  

Purple Martins feed on flying insects which they catch in flight.  Their feeding frenzies provide good entertainment since they fly up to 72 kph ( 45 mph).  If there are adverse feeding conditions for more than 3 days the birds are in danger of starvation.  

In eastern North America the Purple Martin nests almost exclusively in martin houses provided by humankind.  This species prefers to be in colonies.  In the west they are more solitary and often nest in cavities in forested areas and in the southwest in cavities in saguaro cacti.  They use cavities excavated previously by another species.  

The population numbers of this species have been in serious decline over the last 50 years.  It is thought that competition for nest cavities has contributed to the decline.  In the west they have lost nesting cavities by logging operations.  There are likely other serious unknown causes of this decline.  

Purple Martins leave our area in August and September.  At that time large aggregations of individuals can be seen.  In August 1985, an aggregation of about 5000 birds was seen at Fredericton and later at Cambridge Narrows.  

The Purple Martin as a species was first described by Carolus Linnaeus, a famous Swedish botanist, physician and zoologist.  Purple Martins were recognized by our First Nations peoples.  They hung up empty gourds for them to nest in even before Europeans came to North America.  

The Purple Martin is a beautiful bird.  We need to be diligent in finding and correcting the causes of their population declines.  We can start by erecting martin houses and learning how to care for them properly.  There are many books and brochures showing how this can be done.  

Northern Rough-winged Swallow

Northern Rough-winged Swallow - A Rare New Brunswick Swallow

Northern Rough-winged Swallow [Internet Photo]

Last week a Northern Rough-winged Swallow (Stelgidopteryx serripennis) was seen at Welsford.  This is a rare swallow species to be found in New Brunswick.  'Birds of New Brunswick: An Annotated List' lists it as a rare summer resident and visitor.  In past years it has been found breeding in southwestern NB, east to the St. John River and north to Carleton County.  There have been a few scattered sightings in other parts of the province.  

I have seen this species at Scotch Lake, York County, in 2009.  It was a single bird flycatching and perching on wires with Tree Swallows.  It often associates with Bank Swallows and can easily be overlooked since they are similar looking.  

Northern Rough-winged Swallow [Internet Photo]

The Northern Rough-winged Swallow is 13 cm long (5 inches) about the size of the Bank Swallow.  It is a rather drab-looking swallow with brown upperparts, pale brownish throat and breast and white underparts.  Its tail is square.  It is named for the serrations on the first primary wing feathers which can be seen in the photo above.  These are only visible with the bird in hand.  This apparently is a unique feature among birds.  The Greek genus name, Stelgidopteryx, means 'scraper wing' and the Latin specific name, serripennis, means 'saw feather'.  The purpose of these serrations is not known.

Northern Rough-winged Swallow

The Northern Rough-winged Swallow occupies a large summer range in North America, most of British Columbia, most of the very southernmost part of the rest of Canada, and all of the US.  In winter it migrates to Mexico, southern California, and the Gulf Coast  of Texas and Florida.  It nests in cliffs along river banks and underneath bridges.  It builds tunnels in sand banks or it will use natural cavities.  It lays 4 to 8 white eggs which are incubated for 12 days by the female.  The diet is mainly insects caught in flight.  It will take insects from a water surface and it drinks by skimming the water surface.  

Northern Rough-winged Swallow

As you can see by its preferred nesting areas how easy it is to overlook this species when it is with a  flock of Bank Swallows.  The Bank Swallow, however, has a clean white throat and belly with a brown breast band.  Occasionally it might be mistaken for an immature Tree Swallow but the Tree Swallow has a white throat and an indistinct breast band which does not meet in the middle.  The call note of the Northern Rough-winged Swallow is a low, unmusical 'brrrt' sound.  

The Northern Rough-winged Swallow was first described by John James Audubon in 1819 in Louisiana.  This rather rare swallow is interesting and worth looking closely for the next time you see a flock of Bank Swallows.  

Bank Swallow

Bank Swallow - Our Smallest Swallow 

Bank Swallow

The Bank Swallow (Riparia riparia) is our smallest swallow.  It is 12 cm (4.8 inches) long compared to 14 cm (5.5 inches) of the Cliff Swallow.  The Barn Swallow is much bigger of course because of the long tail (17 cm/6.8 inches).  The Bank Swallow spends its summers in most of North America from Alaska to Newfoundland and Labrador south to the central US.  It winters in southern US, Mexico, the Caribbean and South America.  Because it migrates such long distances it is our first swallow to leave in late summer.  The Bank Swallow is one of the few passerines with a nearly worldwide distribution, amazing for such a small species.  It is also found in Europe, parts of the Middle East, Central Asia, Russia, northern Mongolia, and parts of northern China.  In Europe this species is known as the Sand Martin.

The description of this species is simple, upperparts brown, underparts white with an obvious brown breast band.  Note the white throat above the band.  It has a slightly forked tail (notched) but nothing like the deeply forked tail of the Barn Swallow.  It flies with its pointed wings swept backward. Its wing feathers appear slightly darker than its body.  The only species one might mistake for a Bank Swallow are a young Tree Swallow which can have a hint of breast band (although it is incomplete) or a  Rough-winged Swallow.  The Rough-winged Swallow is uncommon here in New Brunswick and it has a 'dirty' brownish throat and no breast band.

Bank Swallow

'Riparia', the genus and species names of this species, means 'river bank'.  They are well named because they nest in burrows made in river banks.  The St. John River has many nesting areas for Bank Swallows.  Near Fredericton this year there is a colony off the head of Aukpak Island.  Because of river erosion the colony makes its burrows fresh every year.  Bank Swallows are very social birds and the colony times the egg laying so that all nests hatch at the same time.  That way more adults are available to find food for the nestlings.  I imagine they know when the insects will be in swarms so the heavy duty feeding occurs at that time.  Bank Swallows also nest along banks of lakes, coastlines, and other wetlands. Apparently in some places they have learned to use man-made structures.

After the site for the colony is chosen the male begins to dig a tunnel.  The female then hovers in front of the tunnel (and male) she chooses and the pair then complete the excavation using their bills, feet and wings.  The Bank Swallow lays 3 to 7 white eggs in a nest lined with feathers and grass in a chamber at the end of a deep tunnel.  Incubation is for 14 to 16 days and is carried out by both adults.  This species feeds on flying insects which it catches on the wing.  Bank Swallows do not sing but frequently make a buzzy 'trrrt' or 'pret' sound.

The Bank Swallow is a threatened species.  Waterway erosion and human 'development' such as road building and quarry establishments are the prime causes.  There has been an 89% decline in the population of Bank Swallows since 1970!  It is time we examined the insect populations and their declines as well as our own destructive behaviours in order to save this species (and many others).  

Cliff Swallow

Cliff Swallow - Housing Engineer

Cliff Swallow

The Cliff Swallow (Petrochelidon pyrrhonota) is a member of the Hirundinidae family (martins and swallows).  This is a family of insectivores which are accomplished aerial-foraging songbirds.  They have compressed beaks with a wide gape (opening).  Their syrinx is differentiated from other songbirds but they are not great singers, at least to our ears.  There are 90 species worldwide and they inhabit all continents except Antarctic and our high Arctic.  Eight species inhabit North America and six species are found in New Brunswick.  Like all insectivorous species, our swallows and martins are suffering population declines at present but according to the literature the Cliff Swallow is doing relatively well compared to the others.

The Cliff Swallow is 14 cm (5.5 inches) long and is distinguished by it square tail, orangish rump, dark blue upper parts, buff underparts, white or buff forehead and orange-brown throat and sides of face.  The genders are similar.  It can be distinguished from the Barn Swallow by the square tail, the light forehead and the buff rump.

Cliff Swallow

The Cliff Swallow builds a spectacular gourd-shaped nest/house under eaves of man-made structures and also on cliffs faces.  The structure is made of mud and saliva and completely encloses the nest except for an entrance hole.  These nests are usually built in groups with other Cliff Swallows.  The nest is lined with grass and feathers. Three to six creamy whites eggs marked with brown are laid and incubated for 14 to 16 days by both adults.  This species has an interesting behaviour.  The female is known to carry one of her eggs in her beak and deposits it in another female's nest.  Cliff Swallows eat insects which they catch on the wing.  They will occasionally eat berries under scarce food conditions.  They are quite vocal emitting a constant chittering sound at the nest.  When the young leave the nest they gather in groups called creches.  The adults can locate their own young in these large gatherings by voice.  

Cliff Swallow Nests

Cliff Swallows are similar in appearance to the Cave Swallow from Mexico and the Caribbean Islands and one should know the difference.  The Cave Swallow has appeared here after severe storms on several occasions.  The Cave Swallow has a pale throat and dark forehead giving it an appearance of having a cap.  Its face is much lighter than the Cliff Swallow.  

Cliff Swallows spend their winters in the tropics where they prefer open country near buildings or cliffs, lakeshores and marshes.  The Cliff Swallow species has been known officially since 1817 when it was described by Louis Jean Pierre Vieillot, a French ornithologist.  A group of swallows is known as a 'gulp', a 'herd', a 'kettle', a 'richness' and a 'sord'.  I hope we will see a richness of Cliff Swallows this August as they gather to begin their migration south.