This past spring and summer I had the opportunity to observe and photograph nesting behaviors of Black-billed Magpies on Antelope Island in northern Utah. Magpies are common in Utah and much of the western US but they’re typically difficult to approach (and very challenging to photograph well because of the contrast of their coal-black and almost pure white plumage) but this pair of birds was so intent on their nest-building activities that they virtually ignored my presence.
Mated pair of Black-billed Magpies
Magpies are monogamous and typically mate for life. This is a mated pair on top of their domed nest in a sagebrush. The male is on the left, the female on the right – males are about 20% larger than females so they are sexually dimorphic. As you can see from the muddy bill of the female they’ve been actively building the mud-bowl found inside the nest. Typically the male provides the heavier branches and sticks for the nest and the female delivers most of the mud for the mud bowl, which probably explains why the female’s bill is so muddy while the male’s is not.
Obtaining mud for then nest
The mud for the bowl of the nest was obtained wherever the birds could find it. When we’d had dry weather they would have to fly quite a distance to get any but after a recent rain they would often get it very close by. This bird has just scooped up a bill-full. When it’s available they’ll sometimes use fresh cattle or bison dung in place of mud.
Mud delivery to the nest
This magpie, presumably the female, (I have a difficult time telling sexes apart unless they’re together) is landing on the nest in front of her but just out of the photo.
More mud for the nest
Here the magpie has landed on the sagebrush where the nest is found with another delivery of mud.
Taking off for more mud
These birds made countless trips for mud and twigs over the many days I was able to observe them. Construction of an entire nest can take up to six weeks. Each nest begins with a mud anchor with twig superstructure which takes 2-3 weeks to build. Then the interior mud bowl – 9 days and the grass lining – 4 days. Approximately 11 days later the female will begin laying her eggs.
Rejecting a twig
Occasionally I would see one of the magpies flying away from the nest with a twig. I presume it was because they found that particular twig unsuitable for construction. This is one of my favorite photographs from the many days I watched these magpies. When the light strikes these birds just right (especially the male) you get an impressive display of iridescence. I was fortunate to get it so well here, especially combined with the upswept tail and the twig in the beak.
Food for the female and young
Only the female incubates the eggs and while she’s doing so she relies on the male for food. In this photo you can see that it’s much later in the spring by the growth of sage coming through the sides of the nest. By this time the eggs had hatched and both parents were providing food for the nestlings. Here, one of the parents is about to deliver a beak full of insects.
Sagebrush with magpie nest, Great Salt Lake in background
This is the sagebrush that contains the nest. The photo was taken in August - long after the nest had been abandoned for the year. The top of the nest can barely be seen at top, just right of center but this very large nest was mostly out of sight within the bush.
Juvenile magpie, on the nest
Circumstances prevented me from visiting the nest as the youngsters were fledging but when I was able to return in early July I found two of the juveniles still at the nest. This is one of them. You can clearly see the perimeter of the top of the nest through the summer greenery.
Interestingly, the two birds of a mated pair sometimes have a difference of opinion about where the nest should be constructed and it’s not unusual for two nests to be constructed even though only one can be used. I often saw these birds raiding another nest in the vicinity for construction materials and now wonder if they had built both nests this year and then as egg laying time approached they decided that the second nest would be a good source of twigs. Speculation on my part but I can’t help myself…
My good friend Mia and I had a wonderful time observing and photographing these magpies and we’re already making plans to do something similar early next spring.