For years, Charles McEwen, of Moncton, New Brunswick, Canada, has been experimenting with videotaping the inside of a Tree Swallow nestbox mounted on the picture window of his living room. At any hour of the day, he could just turn on his television set and have an intimate view into the private lives of the swallows nesting just inches away. With that experience under his belt, Charlie wanted to videotape the action inside a martin house. So, in the Spring of 1991, he built a very special, four-unit martin house (see Fig. 1). The house had a removable, rear, glass wall, with an insulated camera housing mounted behind it. The camera housing had a thermostatically-controlled heater that kept condensation from forming and ruining the camera during temperature and humidity extremes. Since he didn't know which of the four compartments the martins might use, the camera was connected to a remote- controlled base that could pan from one compartment to another. Next, since he wanted to be able to see and videotape what was going on in the nesting compartments, day and night, each compartment was equipped with a rheostatically- controlled ceiling light. Finally, Charlie wanted to be able to hear and record the vocalizations of the birds, so the house was fitted with a sensitive microphone.

The house was positioned in exactly the same spot that an active martin house had been in previous years (about 15 feet from his bedroom). Best of all, Charlie set up a control station in his bedroom so that he could man the controls while observing the outside of the martin house. From this bedroom-based control center, Charlie could watch what was going on inside the compartments through his television set (see Fig. 2); he could turn the compartment lights on; pan the camera from compartment to compartment; hear what the birds were "saying" through an indoor speaker; record their interesting behavioral sequences from his television set, straight into a VCR; and could add verbal commentary (such as wind direction and speed, air temperature, sky condition, and barometric pressure) directly onto the video tape with an indoor microphone.

The exciting part of all this, was that videotaping the inside of a martin nest had never been done before - no scientist in the world knew what went on inside a martin's nesting cavity - but now, thanks to Charlie's genius, we do. At the end of the breeding season, Charlie loaned the tape to the PMCA to view, which we did numerous times. From Charlie's 5-hour tape, we learned many new things about martins. What follows is a brief, verbal transcription of the highlights Charlie captured during the 72 consecutive days he videotaped inside his martin house.

May 21, 1991 First nesting material of the season is brought in. The male and female spend a lot of time in the box together, chirping to each other. The birds make numerous attempts to scratch out a bowl in the bottom of the wooden house compartment. They do this by spinning in the bowl, pushing their breasts flat against the floor with their wings spread. When placing nesting material, they vibrate their beaks against the substrate for several seconds, before letting go of it - almost like a rapid sewing machine, except the motion is sideways. The microphone reveals that the birds in the nesting compartments are subjected to amplified outside sounds, probably a function of being in a hollow chamber with a hole in the side. The birds must put up with the amplified sounds of cars, motorcycles, wind, and other bird calls, all season long. Was surprised to learn that the pair spent a great deal of "quiet time" inside.

May 22, 1991 While nest-building, they come in with material, sing, spin in circles several times, then do the sewing machine, vibrating action. When they rest, they often sit, quietly, head-to-head. At night, Charlie can turn the light on inside the compartment to see how the martins sleep - the light doesn't bother them. They sleep head-to-head, touching, with their heads pointed into the back corner.

May 23, 1991 Much more nest material present today. Each new piece of nesting material is "sewn" into position and is brought in with accompanying vocalizations. The floor in the bowl is still bare, but the walls of the nest are about one inch tall.

May 24, 1991 A brief rainstorm hits. The sound on the metal roof is nearly deafening. The pair comes into the compartment and sings wildly and continuously, during the downpour. They sit looking out the entrance hole part of the time. After the storm, they huddle into the back corner, beak-to-beak.

May 25, 1991 It appears the female is doing more of the nest-building than the male. All of her material placement is accompanied by exuberant chirping.

May 27, 1991 The pair has built nests in side-by-side compartments, perhaps because there are no porch dividers. The pair sleeps in the neighboring compartment, during the daytime, in head-tucked position.

May 28, 1991 The male is in the bowl making a "cheeping" sound like a food-begging chick. The female nudges him to the side of the bowl, like a couple fighting over the covers, the whole time vocalizing loudly. The birds spend a surprising amount of time, each day, sleeping together in the compartment, head-to-head, in the back corner. They chatter back and forth to each other. The male gives his "krieeek" call and the female answers. The first green leaves show up in the bottom of the bowl.

May 29, 1991 The female nudges the male out of the bowl so she can sit in it. She spins in it and pushes her belly flat against it in an attempt to form a bowl. Again, they exchange heated vocalizations and the male joins her in the bowl. They sleep during the day, beak-to-beak.

May 30, 1991 There is so much straw in the nest now, that you can hardly see the bare floor. The male is alternately sleeping in one compartment, with one female, one night, and in the other compartment with another female the next. Is this going to be a case of polygamy? The male just brought in a green leaf and then spun on top of it in the bowl. The female came over to "try the nest on for size," especially just after the male was in it. The male then brought a green leaf into the other nest. He alternates bringing leaves to each nest. He is getting these leaves from a nearby Crab Apple tree. He gives the leaf to the female in the bowl and she "beaks" it repeatedly and places it under herself.

May 31, 1991 The male brings in a green leaf and the female gets out of the nest so he can place it. Charlie speculates that perhaps they sleep up against the heated glass back wall to keep warm on cold nights.

June 1, 1991 Female in neighboring compartment has been missing for a couple days, but male is still sleeping in there occasionally, especially during periods of drizzle. I believe this scratching in the bottom of the nest is an innate attempt to scratch a bowl, just like when they nested in old woodpecker holes with rotten wood in the bottom. Charlie feels martin landlords should supply compartments with a granular material so that the martins won't have to carry in so much material, and they can just scratch a bowl. Perhaps an inch of fine, packed sawdust.

June 2, 1991 Charlie turns the video and light on at 1:00 AM, and the pair in the original compartment are sleeping together. At 8:30 AM, the female is bringing in green apple leaves. Charlie can watch from his bedroom window for approaching martins, then look down at his monitor to see what is going on inside the compartment. Charlie feels that besides keeping nest parasites in check, green leaves may create a smoother, softer surface for the eggs. The female wiggles, squirms, pushes, and spins, every time she goes into the nest bowl, all movements designed to shape the bowl to her liking. The male is escorting the female between the apple tree and the compartment. This is known as "mate-guarding." The male brings a leaf and does the ritual wiggle, squirm, push, and spin in the bowl. At 6:08 PM, it is now raining quite hard and the birds just came in. The rain is so loud to the birds in the compartment, it sounds like hail on a tin roof. The female immediately went into her head-tuck, sleeping posture in the nest bowl.

June 3, 1991 The compartments are 7" wide, but the female's tail is touching the one wall and her head is only 1/2" from the other wall, despite the fact that she is sitting in the bowl, diagonally.

June 4, 1991 The male is making several trips to the nest with green leaves. A new male is sleeping in the adjacent compartment, alone. The female at that compartment has not been around.

June 5, 1991 6:53 AM: It is 42 degrees F. The pair is still sleeping in the house, despite the sun being up. It is partially cloudy, and too cool to forage. Charlie pans between the neighboring compartments. The male that spent the night in the vacant compartment, is gone this morning. The birds are very sensitive to what is happening to the outside of their house. If something lands on the house, they run to the front to look out the entrance. The birds are preening and stretching while sitting in the nest bowl. The house is swaying quite a bit in the wind. At mid-day, the pair is sleeping in the adjacent compartment. They slept there all afternoon, with 20 m.p.h. winds, and 45 degrees F. The birds are conserving energy by sleeping and puffing their feathers.

June 6, 1991 From 10:00 AM on, the birds were gone most of the day foraging, since they couldn't feed yesterday. At nightfall, extensive preening is being done by the female, who is sitting in the nest bowl. The male is sitting in the entrance hole, looking out.

June 9, 1991 5:32 AM: The female is sitting alone on the rim of the nest. The male is nowhere to be found. The female's white, axillar feathers are sticking up and are quite conspicuous. At 10:02 AM, the male brings in a leaf. The female and male sit in the nest bowl for long stretches of time, even during good weather, despite there being no eggs.

June 10, 1991 More leaves are being brought in. The female spent most of her time today in the nest. Charlie assumes the egg is not far away.

June 11, 1991 During her bowl-shaping behavior, the female cuddles down, lowers her shoulders slightly, and wiggles back and forth.

June 13, 1991 8:00 AM: Female is prostrate in cup having egg-laying contractions. Her breathing is heavy and labored. Her head is pressed against the wall, her cloaca near center of nest bowl. About every 3 seconds she goes into a pronounced contraction - looking like she is trying to force the egg down the oviduct. The egg came out and is wet and shiny. The female seems exhausted. 8:03 AM: She gets off the egg, looks at it, rolls it with her beak, then sits on it. She spins in the bowl on top of it. She didn't leave the egg until 9:49 AM. At mid-day, the male is on the egg, and she allows this as she sits on the edge of the nest, nearby. In the evening, the male and female sleep together in the nest, the female on the egg. She is not allowing the egg to get chilled. They sleep, side by side, head-tucked.

June 14, 1991 7:53 AM: The female has to squeeze in beside the male in bowl. They didn't make the bowl large enough for two birds to sleep in it. Later, her contractions start again. She laid her second egg while just squeezed in beside her mate. Charlie comments that this couple shows a lot of togetherness. The female struggles to get both eggs out from under the brooding male. They compete to sit on the eggs. It is windy and cold this AM. They are keeping the eggs from getting chilled.

June 15, 1991 Male brings in green leaf and presents it to female and she chatters to him. 8:20 AM: Temperature is 47 degrees F., sunny. The female is prostrate and is having egg-laying contractions. Heavy breathing - eighty breaths per minute. She arches her back slightly, wiggles, then pushes hard, right down through the tip of her outstretched tail. She does this repeatedly. She jerks wildly when the egg finally comes out.

June 16, 1991 Three eggs are seen in the nest at 7:25 AM. She hasn't laid her forth egg yet today. No one is on the nest currently. Later, the female sits on the eggs, then lowers and spreads her wings. The male sidles in beside her. Female is preening. 9:07 AM: Male brings leaf. She ignores it. He stands on top of her head. She is having contractions - very unique, rhythmic, tail-pumping action to get the egg to come out. The egg came out at 9:11 AM. She sits motionless and exhausted. Soon she is spinning on the eggs and settling down on them. She fine-tunes their position with her bill. She now rests on the eggs. She is breathing at about 50 breaths per minute, now. At 10:26 AM, she finally finishes her rest and leaves the compartment. Later, the male is on the eggs.

June 17, 1991 7:25 AM: The male is on the nest with 4 eggs. The female has left to feed. The male spends a lot of time on the eggs in the female's absence. He has been on for over 30 minutes. He is panting with his beak open. Why? During the first two eggs she laid, on the 13th and 14th, there was no food available for her because of the poor weather. No egg laid today. Full clutch of only 4 eggs for an ASY pair - unusually low! Adult pairs usually have 5 or 6 eggs.

June 18, 1991 Male brings in green leaf. Female preens while she incubates.

June 19, 1991 Male on eggs. Female comes in and chirps repeatedly at him. He won't leave the eggs. She has to crawl right under him before he'll leave his incubation duties.

June 20, 1991 Male brings in aspen leaf for incubating female. She chirps at him.

June 22, 1991 Martin eggs have to be tough - the birds spin around on them so much. The female can sometimes get the male to relinquish his incubation duties just by approaching the nest bowl and chirping repeatedly. It doesn't always work, though. His paternal instincts are strong. The male wiggles back and forth on the eggs, just as the female does, to position the eggs under himself.

June 24, 1991 Male is on the nest again this morning. The female has just gone out. Males spend a great deal of time on the eggs, perhaps almost as much as the females. But can what they are doing be termed "incubation," since they do not develop a brood patch? Female brings in an aspen leaf. Female attacked by another male on the porch, while her male was in on the nest. He went out and chased the other male away.

June 25, 1991 Both the male and female do a lot of side-to-side wiggling when they first settle on the eggs.

June 26, 1991 Female brings in green leaf and male gets off the eggs. Male and female communicate a great deal to each other in the nest compartment, using chortles and chirps.

June 27, 1991 No sign of hatching yet. A parent has been on the eggs nearly constantly. They rearrange the eggs and green leaves often. Charlie feels the male spends about 1/4 of the time on the nest.

June 30, 1991 Two young nestlings hatched this AM. Exactly 15 days after the penultimate (i.e., the next-to-the-last) egg was laid. [This is when incubation typically begins.] Eggshell hemispheres have already been removed. Female begins brooding young and two remaining eggs. The nestlings are bright pinkish-orange, naked, and their eyes completely closed. They wiggle around a bit. The mother brings in the first bits of insect food. She places it in the open, begging mouth of the young. Charlie thinks they are feeding by regurgitation. No insects seen in mouth or beak of parent. It's possible, because she goes from young to young and seems to swallow back down what they don't take. A parasitic blowfly is seen walking around the nest, young, and eggs. It is in among the green leaves, apparently laying its eggs. It pauses in several locations, then moves on. When the hen comes in with an insect visible in its beak, the blowfly flies to a different location and hides. The hen feeds one nestling a couple of insects, then apparently regurgitates to the other. Now she settles in on the young. At 7:00 PM, still only two have hatched. Charlie comments that he hasn't seen the male all afternoon.

July 1, 1991 6:33 AM: The third young has hatched. The female still wiggles in on top of them, even while brooding. Charlie feels the male is not allowed in while hatching is taking place, because he hasn't seen him come in since hatching began. He just sits outside.

July 2, 1991 6:25 AM: The last egg has hatched in last 24 hours. Only 3 young in nest, though. One young fell to the ground and died. Charlie doesn't know if they threw it out onto the porch on purpose, or by accident. He saw it squirming on the balcony before it fell. Charlie feels one got caught in her foot when she may have made a dash toward the entrance to chase the male away. The young tangle around each other to stay warm, plus the shape of the leaf-lined bowl keeps them rolled in on top of each other. The female feeds the tiny young, then searches for, and finds, a fecal sac, which she instantly eats in an effort to keep the nest clean. Next, she broods them.

July 3, 1991 8:00 AM: The chicks have grown quite a bit in the last 24 hours. The female has left the nest, searching for food. No male seen. Young left unattended. Air temperature is 50 degrees F. It is calm and sunny. The male of this nest is keeping company with other martins. She is doing her best to keep him out of this nest. Why? This seems maladaptive. Female feeds one young a relatively large insect and the young has to work to swallow it. She immediately goes to the other end to "greet" a fecal sac.

July 5, 1991 At 7:00 AM: It is 55 degrees and the female is out foraging. Charlie says the female flies instantly quite high - an indication of where the insects are, plus the safest place to be in case of a hawk attack. She brings back a medium-sized moth, with its wings still fluttering. The 5-day-old young have difficulty swallowing it. Next she brings in a small butterfly. The nestling just holds it in its closed beak. The female tries to take it away and this forces the young to swallow it. More brooding.

July 6, 1991 The young are still featherless and naked. The "five o'clock shadow" of developing feather tracks are beginning to show on one nestling. This is the first day Charlie hears a chirp from the young. First large dragonfly delivered. Female chirps at the young to take it. The first one can't get it down, so she takes it away and gives it to a second young. It has no trouble swallowing it. Later, an even larger dragonfly is brought to the young, which are only 6 days old. All the young beg and chirp, but none take the prey. Finally, one gets its down, but only after the female tries to pull it out of its throat several times. I am sure this forces them to swallow it completely, or lose it. The female comes in searching the nest for fecal sacs, then she sits on the young to brood them.

July 7, 1991 The female is still brooding young. They are getting quite large, but are still featherless and naked. Female now flies off with a fecal sac, rather than eating it. The young are over seven days old today. Every little noise or vibration causes the young to jerk up and food beg. Their eyes are still closed. Another large dragonfly is brought in. The nestling swallows all of it, but leaves tail sticking out. Female tugs on the insect's tail to get young to finish swallowing it. It does. After each feeding, the female broods the young. She aggressively walks and spins on them, then looks under them. Is she trying to force them to defecate?

July 8, 1991 Female still brooding. The young have really grown. Still no feathers on them. The young are wrapping themselves around each other in the nest for warmth. The nest is very clean. The female comes in and the young beg for food. Their eyes are still closed. She pokes their rear ends, but none defecate. Male came in and started pecking the heads of the young. Female came in and bit him. They spin and spin in circles, fighting within the nest. He flies off. The female eats the fecal pellet of an eight-day-old young. She is successfully raising these three, alone.

July 9, 1991 7:36 AM: The temperature is 60 degrees F. The 9-day-old young are being brooded by the female, but the three young are so big she is having a tough time covering them. You can see her brood patch as her flank feathers are spread widely open. The young are beginning to take on a gray appearance from all the feathers beginning to show under their skin. The male landed on the railing, outside, and called. She went over to the entrance and told him to take off. He did. The eyes of the young are just beginning to open. She is poking at their fat bellies to get them to defecate. They haven't been fed yet today and are quite hungry and squirmy. She is preening while she broods. She is always sticking her head under the bundle of young. Is she looking for fecal sacs, or blowfly larvae? Later, the male came back in the compartment. He doesn't sit on the young, he just pecks the little runt, then sits next to them. Charlie witnesses the attacks and goes out and shakes the house. The male martin stops pecking the heads of the young, but he doesn't leave the nest compartment. He did no obvious harm to them. Later, the female is brooding the young when Charlie turns the rheostat up to make the light brighter. The young respond by jerking their heads up to food beg. Any abrupt changes in light level (either on, or off) trigger the food-begging response.

July 10, 1991 7:09 AM: It is 55 degrees F. Female is still brooding the young. At noon, she brings in a single, large dragonfly. It took her 6 minutes to leave and return with the dragonfly. After each feeding, she pokes her head in between and underneath the young looking for fecal sacs or blowflies - still a mystery. She is meticulous in her searches.

July 11, 1991 8:30 AM: It is 52 degrees F. The female is sleeping in the bowl with the young off to her side. When she wakes up, she immediately starts looking underneath them. They are now on a bare, wooden floor. What ever she finds, she eats or tosses off to the side. She spends several aggressive minutes digging and scratching under them. She has all the nesting material scratched to the side. The green leaves are gone. The female comes in and again searches underneath the young. She is certainly a very good housekeeper. One young is trying to swallow a long piece of nest-material straw. Did it mistake it for a prey item? Charlie feels very certain that aluminum houses and painted wooded houses should have soft floors in them, so the birds can dig a bowl in them. Charlie feels a soft insulative material, such as foam, would be best for a pre-formed bowl. A friend of his put a 1" thick foam layer in the bottom of one of his martin nests, and the birds scraped a bowl in the bottom of it and successfully raised young in it. He did it because he felt metal houses are too cold for martins.

July 12, 1991 7:00 AM: 55 degrees. The 12-day-old young are almost too large to be brooded, so the female sits right next to them while she sleeps at night. The male still comes around and looks in the entrance, but hasn't been in for a while. The female searches under the nestlings again, at great length. Charlie has seen the mother pick up dropped flies and moths in the nest, to eat them. She is still trying to brood her young. Their wing feathers are beginning to show. She is brooding the runt, more than the others, because it isn't developing as fast as the others.

July 13, 1991 8:30 AM: The temperature is warm. The nest is disintegrating. The runt is dropping back in size relative to the other two siblings and is having trouble maintaining its balance. She is feeding smaller insects this morning, probably because that is all that is available.

July 14, 1991 9:11 AM: It is raining and 58 degrees F. The runt is out of the bowl, in front of the nest. It appears weak and dying. The female is sleeping to the side of the young in the bowl. At 2:16 PM, the runt is back in the nest. Female is sleeping on the edge of the nest bowl, with eyes closed and head drooped. The young have crawled in on top of the sleeping mother - reverse brooding!!??

July 15, 1991 The runt died last evening. It is dead in the nest bowl. The female looks at it, then searches underneath the living ones. 8:30 AM: The female is now brooding the dead baby, trying to warm it. She is also trying to brood the others. Later in the morning, Charlie's hand is seen going in and removing the dead runt. Now there are only two chicks for the lone female to raise. When the female came in, she appeared to look around for the dead young. Later, a subadult male is in the compartment, looking at the young. He has been in a few other times, also. Charlie feels he is just curious. He has not been aggressive toward the young. The younger of the two siblings is beginning to look quite stunted and backward, relative to the oldest nestling.

July 16, 1991 7:43 AM: The subadult male visitor is back in the nest in the morning. The mother is out looking for food. He has made several visits this morning. Both young are able to preen already - they are 16 days old.

July 17, 1991 8:03 AM: The temperature is 68 degrees F. The young are feathering out nicely. The young spend a lot of time preening their rapidly-growing plumage.

July 18, 1991 8:05 AM: The temperature is 68 degrees F. The young are stretching. There are several vagrant visitors to the house. The female comes in and again picks and searches under the young. The nest is spotlessly clean of all fecal droppings.

July 19, 1991 7:18 AM: The temperature is 66 degrees F. The young are preening themselves. Female appears to be brooding them partially. She is on top of them, with her breast feathers clearly spread open. The young, however, are well-feathered now. They are 19 days old. The smaller bird is breathing hard. The mother went in and fed the young a large dragonfly, the young grabbed it, swallowed it, spun around and defecated on the nest rim, and the female left with the fecal sac in her beak. When the young defecated, it spread its wings wide open for balance. An ASY male is now in the nest harassing the young. He nudges them out of the bowl. Charlie raps on the pole and all three of them scramble way to the back of the compartment, displaying a typical fear response.

July 20, 1991 8:54 AM: The temperature is 74 degrees F. The young are still preening the feather sheaths off their growing feathers. The smaller one is still breathing hard.

July 21, 1991 8:34 AM: It is 72 degrees F. Smaller sibling is still breathing abnormally. He must have some kind of a respiratory problem. Male was inside the compartment again, picking on the young.

July 22, 1991 Charlie had to go up and clean the glass between the nestlings and the camera, because it had gotten quite smeared and dirty, and it was affecting the quality of the video image.

July 23, 1991 6:41 AM: The temperature is 50 degrees F. The young have their feathers fluffed up to keep warm. Smaller nestling is breathing hard. Oldest bird is now practicing fluttering its wings. Feather sheath fragments are flying all over the inside of the compartment.

July 24, 1991 12:21 PM: 74 degrees F. Larger sibling scratches its head with its foot over its wing. The feeding rate has dropped off as the young reach this age of 24 days.

July 26, 1991 7:40 AM: The temperature is 62 degrees F. The sibling with the breathing problem is falling behind in its development. The nest is getting a little crowded, even though there are only two nestlings, and the compartment is 7" by 12".

July 27, 1991 8:40 AM: It is 60 degrees F. The runt waits for food near the entrance hole. Both it and its sibling do wing fluttering as they beg for incoming food from parent. White axillar feathers visible on the young. 11:20 PM: Mosquitoes in the nesting compartment bothering the young and taking blood meals! The nestlings are awake, upset, and fluttering. Charlie is concerned that the mosquitoes are vectors in diseases that affect the martins, especially when young, naked, and helpless.

July 28, 1991 9:02 AM: Older nestling exercises its wings often.

July 29, 1991 12:27 PM: The temperature is 78 degrees F. The two youngsters went out of their nesting compartment, onto the porch and into the neighboring compartment. They spent the night in there.

July 30, 1991 Morning: Mom comes in to feed. The young wing flutter to beg for food. When they flutter, their outstretched wings hit on each side of the walls of the 7" by 12" compartment. Even 7" is not wide enough for their wingspread. Charlie feels his video proves that the 6-inch cubed, compartments in commercial, aluminum houses are too small for martins. Charlie favors porches and railings, as he says it gives the young a place to exercise their wings before they take their first flight. Charlie feels one of the reasons martins may prefer gourds so much is because they have a bowl-shaped bottom that helps holds the nest together. The smaller bird fell off the veranda and hit the ground today. It couldn't fly. Charlie put it back on the veranda and it ran into the compartment. It may have been injured by the fall. The nestlings are 30 days old today.

July 31, 1991 8:12 AM: The temperature is 60 degrees F. The younger bird with breathing problems died in the night, back in the original compartment. Charlie had it analyzed. [It died of a fungal infection (Aspergillus fumigatus) of the lungs and air sacs.] The older bird is in the neighboring compartment. It is 31 days old today, due to fledge. At 9:35 AM, the young fledged. Seventy-two days from nest-building to fledging. Only one bird survived from a clutch of four eggs. The lack of help from the male certainly contributed to the female's poor reproductive success.