## Enjoying the Birds of the Ottawa Valley

### July

A slow month for new species. It's a great time to study breeding birds, and to develop some techniques for counting birds that will add interest to your observations.

The key to counting breeding birds lies in two words: territory and habitat. Within suitable habitat, birds space themselves out at surprisingly regular intervals. The spacing reflects food supply imperatives. So, the first thing to do for a species is to find an area where it is present, and to estimate its spacing.

In open country, use your scope (to see areas not affected by your presence) and compare the spacing to that of fence posts (about four meters). Then, allow for the foreshortening effect of looking through the scope: if a savannah sparrow is seen perched in the grass tops every third post, within an apparent distance from the fence equal to that between posts, and you are using a 15x scope, then you are really covering an area 15 fenceposts deep. Your territory estimate is thus 3x15 fenceposts.

For larger birds, count them, then count posts to determine the field area. For example, four meadowlarks singing in a field 40x50 fenceposts. How's that for a compromise between thinking metric and imperial!

In wooded country or at night, use your ears. If 10 birds are heard in a 2 kilometer walk, and you can hear one up to 100 meters each side (a 200 meter width) of your path, then the territory size is 2000 x 200 / 10 = 40,000 square meters. How do you estimate 2 kilometers? Run your finger along the route on the 1:50,000 map and compare it to the 1 kilometer grid squares. How do you estimate how far you can hear? This depends on the bird, how noisy the day is, and your hearing. First, walk along beside a fence, counting your steps, so that you can convert steps to fenceposts (5 or 6 steps per fencepost for most people). Then, draw a picture of an old fashioned clock with the numbers 1 to 12 on it. Hold it in front of you, with the 12 facing directly forward, the 6 facing behind. A bird directly to your left is referred to as "at 9 o'clock". When you hear a bird at 10 o'clock, walk forward (in the 12 o'clock direction) until it is at 8 o'clock. The distance you have just walked is the distance from your path to the bird. The same thing holds for 2 o'clock to 4 o'clock. 100 steps? 20 fenceposts. With owls, use your car and its odometer.

Territorial songbirds sing mostly from specific perches located around the edges of their territories. Singing is usually most noticeable when two males face off across their territory line. Most males, resident or not, raise the territorial imperative in another male. But, some birds recognize their neighbours as individuals, by voice, and need sing only from the territory center once neighbours are established. There can be two or even three relaxed territory holders between two singing savannah sparrows, a fact that leads even experienced ornithologists to greatly underestimate their numbers on occasion. Listen to the middle section of the song to recognize individuals, or count nests by a hands and knees search after breeding is over, if you would count them accurately.

Your second task is to determine the area of suitable habitat within your study area. A topographic map, suitably scribbled on in the field, is a great help here. Some birds establish territories primarily along lines, like red-winged blackbirds along cattail ditches. Measure the total length of such lines in your area using the 1 kilometer grid lines on the map. Others cover entire areas in all directions, like red-wings in marshes. Measure the areas by counting grid squares. Some species nest in a restricted portion of suitable habitat and just forage in the rest (bobolinks) whereas others by and large feed around their nest (meadowlarks); allow for this. The Audubon Encyclopedia gives territory sizes of many birds if you doubt your eyes and ears.

Here is an example of how these methods can change your population estimates. In lush recently overgrown pasture, song sparrows are mostly found along fence rows where the shrubs and highest grass tend to be. Savannahs tend to fill all the featureless areas not taken by songs. Also, savannahs shut up and run along the ground like mice for large distances around intruders. As a result, songs are much more visible and, being closer, more audible. However, where fields are large, there can be many more savannahs. In the Cumberland area, my estimate is five times as many savannahs as songs in this habitat. By normal methods one would be certain it was the other way around. (By the way, the Ontario Breeding Bird Atlas unilaterally removed, without comment or consultation, all reports of high densities of savannahs from their final publication.)

The final step is to divide habitat area by territory area, and believe the result. Don't forget that there are a million square meters in every one of those blue square kilometers on your maps. If just 20% of an area is good nesting habitat for a species, and its territory is 2000 square meters, then there really can be 100 pairs per square kilometer. (Savannah sparrows have 80% breeding success on only 600 square meters.) This technique will make you appreciate just how few birds of the Valley you are really seeing. It should encourage you to look for more.

To estimate the number of flying birds in a moderate-sized flock, count ten birds, then trace the circle surrounding them with your eye. Then, trace out equivalent circles among the rest of the flock. Six circles? Sixty birds. For large flocks, trace out ten adjacent circles of ten each, then count the resultant circles of a hundred. A common mistake is to overestimate the numbers of large birds like geese, and to underestimate the numbers of small birds like redpolls.

When birds roost in large numbers, they usually approach the roost along a few corridors for up to an hour around sunset. They then mill around the roost area until dark, swirling impossibly. To estimate their number, identify spots away from the roost where the corridors are well defined. Then, count samples of the birds as they fly in. For example, if a one minute sample yields 100 crows, and crows flew in for about ten minutes, then 1000 crows used that corridor. If there are three corridors, used about equally, then the roost contains about 3000 crows.

At Pembroke, you must combine both of these flock-counting techniques, since the swallows arrive at a peak rate of 10,000 per minute! Practise on a simpler case, such as the 5000 ring-billed gulls that fly up the Ottawa past the Remic Rapids during the three hours prior to sundown.

### August

Migration picks up again now, with shorebirds whipping through that normally migrate by another route in the spring. Watch for white-rumped and buff-breasted sandpipers and sanderlings in particular (and long-billed dowitchers in September). With any luck, the water is low enough on the Ottawa that mud flats at Shirley's Bay, Ottawa Beach, and Wychwood are exposed. (Keep touring the sewage lagoons, though.) Later in the month, start checking ploughed fields for any plovers you are missing, like lesser golden, especially near Fallowfield and Greenbank roads.

Fall, with immature and moulted birds around, is the time to study feeding and flight actions to help separate species. A spotted sandpiper, of course, is easy. The combination of the rear end of a bump-and-grind dancer, and its stiff shallow wing beats interspersed with glides, make it unmistakable. Every shorebird has something unique about its feeding habits, for that is why it survives as a separate species. Shorebirds spend most of their life migrating in flocks combined with other shorebirds. Two species can not rely on exactly the same ecological niche, or one will increase and out-compete the other.

Plovers spread out all over a sand beach, while sandpipers keep together, close to the water line. Plovers run about with head erect, then stab suddenly at a morsel they see. Sandpipers probe the sand, locating their food by feel. A sandpiper feeding in dryish mud (with grass tufts) is probably a pectoral or least. Sanderlings don't have ocean swell to chase up and down on the beaches of the Ottawa, but they still run along the water's edge the same way. Stilt sandpipers and short-billed dowitchers feed with a vertical "sewing-machine" motion. (One of these days you may spot one "sewing" at a 45 degree angle, and realise you've got a curlew sandpiper.) Greater yellowlegs, which can look similar to stilt sandpipers, run through deep water, with extravagant motions, while lesser yellowlegs dab around with faster but smooth motions.

By mid-August, your attention will return to warblers, although identifying some can be a mind-bending strain at this time of year. Roger Tory Peterson once remarked that "if at the end of ten years you can say that you know your fall warblers, you are doing very well". The letters UFO take on a new meaning when you watch warblers!

There is only one secret to migratory warbler identification: study your field guides the night before. Many species are in our area such a short time that it is simply unrealistic to expect to remember them all from one year to the next. The optimum strategy, once your binocular hits a warbler, is to concentrate first on the head and face pattern. Most, even in fall, can be identified solely by this. Next, check where the underside colour changes: throat, breast, or belly. If the bird is still visible (usually it won't be), check for wing bars, then the rump colour. (If it's still there, pick it up and take it to the Museum. You are not supposed to count dead birds!) Review verbally to yourself what you have seen, before you open your field guide. The guide pictures will blur your visual memory, since they are so similar.

Another useful trait of warblers that aids identification is that most occupy habitats separated from other species solely by height above the ground. They are more variable in this respect during migration than when breeding. But, palm, ovenbird, mourning, Canada, waterthrush and yellowthroat will almost always be found below eye level. Tennessee, parula, blackburnian, pine and blackpoll will rarely be found elsewhere than in tree tops (particularly during spring migration).

### September

Migration month for thrushes. If you missed grey-cheeked thrush in spring, check Britannia with especial care after mid-month. Most fall migrants fly over our heads at night, calling as they go. (Young birds call much more than experienced ones, so little calling is heard in spring.) Find a quiet spot, settle down at sunset, and just listen. The peak time for calling seems to be two to three hours after sunset, mid-August for warblers, mid-September for Swainson's thrush, early October for hermit thrush.

Some birds use calls at night that they don't use during the day, so pinning a sound down to species can be difficult. I have been able to find confirmed descriptions of the calls of only two such species. Grey-cheeked thrushes call a low nasal "breeer" on a constant pitch, while Swainson's thrushes call a higher whistled "vreeu", rising then falling again in pitch. Another species numerous here, possibly wood thrush, uses a medium pitched flute-like whistle on a constant pitch.

There is an easy and effective technique for you to count night migrants. Pick a night when the moon is nearly full and the sky is fairly clear. Set up a 20x telescope on the moon, and watch for silhouettes. For your eyes' sake, watch for ten minutes, then rest for five. Repeat for ninety minutes to get a one hour count. Peak numbers occur near the middle of the night, but the hour before midnight yields numbers close to the peak.

Most birds migrate at an altitude of 700 to 1000 meters. (They fly lower during the first two hours after sunset, also later in the night as birds come down for the next day.) At this altitude, the cone of light from the full moon averages 8 meters wide. (The actual cone size depends on the altitude of the moon and several other factors, but 8 meters is a reasonable average.) The Valley is 200 kilometers wide. Small night migrants fly essentially uniformly across the sky. So, multiply your moon count by 25,000 to estimate how many passed over us all during the same period. If you watch for only one hour near midnight, multiply by a further six to estimate the total night passage. After a few years, when a full moon has occurred during both warbler and thrush migration periods, you will see why I think 100 million birds migrate through the Valley each year. (Again, as of 1985. 2002 studies are showing up to a factor of two decrease from 1985.)

Keep your rabbit foot out for a bald eagle anywhere around water, and for a Caspian tern around Ottawa Beach. Watch the sewage lagoons for a bobbing bird that spins in circles as it feeds. If it does this from dawn to dusk, check carefully for red phalarope. (Any phalarope spins at times. But, Wilson's mostly walk on the shore here.)

### October

Ottawa River month. The water becomes blanketed with flocks of diving ducks, including black and surf scoters and, occasionally, red-throated loons that usually bypass the Valley in spring. If a cold front moves down from James Bay late October or early November, get out to the end of the dike at Shirley's Bay. Such a front on November 12, 1984, produced over 2000 loons. Huge flocks, and rarities, are driven off James Bay when it freezes over in November, so a November front is especially important for a list builder.

When loons land, they have to push forward with their feet to keep in balance as their airspeed slows. Until they learn to do it, they tumble head over heels.

From the dike, you will also have the best chance of seeing a golden eagle at this time. They soar down the Ottawa along the edge of the Gatineau Hills, then, generally between Quyon and Britannia, head southwest for the St. Lawrence. Golden eagles sometimes fly like a rough-legged hawk, so don't dismiss distant specks without a check, especially between 10 a.m. and 1 p.m. when they usually appear.

On the river, a tight coordinated swimming flock will be scoter or brant. Brants ride high in the water. White-winged and surf scoters can be tough to separate at this time, since many are still in eclipse (black) plumage. Many birders consider the bill shape to be the only trustworthy field mark at a distance.

Although the field marks for separating scaup are shown in guides, they are not too well explained. Greater scaups have a longer bill and sloped forehead, with the "point" of the head forward of center. Lessers have a steeper forehead, with the head point behind center. Head colour is not trustworthy under many river lighting conditions. When they fly, however, the difference in their wing stripe is reliable.

A Valley specialty is the separation of female Barrow's goldeneyes from common goldeneyes. (Taverner wrote on this subject in 1919.) Bill colour is useful only in spring. The bill of a first-year female Barrow's is yellow only at the tip. Several female common goldeneyes have been obtained with a bill yellow right to the base. Even though a Barrow's bill tends to be orange-yellow compared to a common's lemon yellow, you can't trust this feature unless ice has concentrated the birds close to shore. The bill of a Barrow's is a bit stubbier than that of a common, and its forehead rises more sharply from the bill. Even this feature, though, is often obscured by the goldeneye habit of leaving head feathers erect for several minutes after splashing down. When you find separating scaup easy, try goldeneyes!

A useful technique for checking such subtle field marks as scaup and goldeneye head shapes is to break off and look at other birds for five to ten minutes. Then, return to see if you can still spot the difference you thought you saw earlier. If you can't, don't assume the bird flew away. The human brain has a great aptitude for convincing itself that angels can dance on pins and such like.

A sharp-tailed sparrow is a possibility now, along water edges of any kind. It has a very laboured flight, more like a rail than a sparrow, with its skinny tail pumping like crazy in unison with its wing beats. Any bird that flies with any grace at all can be immediately discarded when you are looking for it.

### November

Dump Month. Especially on Trail and Cook Roads, for that is where the rare gulls turn up. Working the dump separates birders from naturalists with despatch. The scenery, and the continuous beeping of reverse horns, makes the gulls the only tolerable things around.

The thousands of ring-billed and herring gulls do not vacate dumps during these times, and most of the rarities are first-year birds, so you need a special skill to find them. To acquire it, the right brain training technique is useful. (See "Identifying Birds".) Sit where both herring and ring-billed gulls are flying, close enough that you can see the colour of their feet to separate them. Watch each flying. Ring-bills typically weigh only half as much as herrings. After a while you will begin to see that ring-bills seem to float on their wing tips a bit like a tern, compared to herrings that plough through the air. Front on, a herring looks like a bulge with wings stuck on the top, whereas a ring-billed looks more like an integrated wing-body.

Once you can spot this difference, start scanning all the wheeling birds. Most rare gulls fly differently from herring and ring-billed. Among the white-winged gulls, icelands float and glaucous plough. A greater black-backed has the head and shoulders of a Japanese sumo wrestler, while a lesser black-backed has similar proportions to herring. After five minutes or so, you should begin spotting them if there are any there.

Then, "just" wait until they land, get them in the scope, and work on the field marks. The bill-to-head size ratio is the first thing to look at. Look next at how far the wings protrude beyond the tail. Generally, the smaller the gull, the more the wings extend beyond the tail. Only then, look at the back pattern. It's more variable than body proportions. Don't forget that many gulls hybridize. The Museum has several specimens of herring X great black-backed that experts mistook for lesser black-backed.

### December

The month for irruptive species that missed the Valley the previous winter, for Christmas Bird Counts, and for getting ready to better your total next year.

It's the time when you may be writing down a lot of bird names on a sheet. There is a simple method of abbreviating bird names that is useful shorthand when taking notes on many species, in the field or over the telephone. The method consists of five rules:

1. If the name is 1 word, use the first 4 letters. For example, BRAN for brant,
2. if 2 words, use the first 2 letters of each (WODU wood duck),
3. if 3 words, use the first letter of each of the first 2 words, the first 2 letters of the last (PBGR pied-billed grebe),
4. if 4 words, use the first letter of each (GWFG greater white-fronted goose).
5. If the result duplicates an abbreviation, change the less common one. To ensure that you do not make a mistake, change both.

The locally-occurring exceptions, together with optional changes in brackets to avoid errors, are:

• GRHE green-backed heron (to avoid GBHE great blue heron)
• RIPH ring-necked pheasant (RNPH red-necked phalarope)
• BDOW barred owl (barn owl gets written in full here!)
• BKSW bank swallow (BNSW barn swallow)
• NOSK northern shrike and LOSK loggerhead shrike (NOSV northern shoveler)
• BPWA blackpoll warbler (BBWA blackburnian warbler)
• CRWA cerulean warbler (CEWX cedar waxwing and BOWX bohemian waxwing)
• Prothonotary warbler and prairie warbler both get written in full here, with exclamation mark.

Finally - you started off to learn how to get 250 species in a year, didn't you? Here are some numbers to show three views of the rate you can list species, within the OFNC Region, to reach that goal.

The year column shows how fast your year list can grow. The month column shows how many species you can get each month. You will only reach 250 for the year if you try to see as many species as possible each and every month. The critical column shows how many of the year's birds you must miss if you are out of town for the month. (My computer insists that you can reach 250 species if you miss an entire month. However, only Bruce Di Labio has.) All the numbers are based on the number of species listed, collectively by all observers reporting to The Shrike, for 1981-5.

```         year  month critical
month    list   list species
January    76    76     0
February   84    71     0
March     108    98     1
April     166   160     1
May       243   222     7
June      248   182     1
July      251   174     1
August    255   187     2
September 261   204     4
October   265   171     2
November  268   120     3
December  270    98     1
```