This fall we have had an invasion of Northern Cardinals into New Brunswick. The term 'invasion' is used to indicate the movement of a population of what normally would be permanent residents elsewhere into new territory. The terms, 'irruption' or 'incursion' are also used for this movement. The movement is without periodicity, i.e., it does not necessarily repeat itself annually. Northern Cardinals are generally a non-migratory species so to see hundreds of them move into New Brunswick is an unusual phenomenon.
We have received reports of Cardinals in the last 6 to 8 weeks from all over the province, even from areas where they have not been seen before. Often these reports include multiple birds, 3 or 4. One report from St. George was of 13 individuals at a feeder area. This is unprecedented here. Several reports are from the north or the Moncton area or east coast where before a Cardinal was an unusual find.
So what is happening? The examples of movements among bird populations which do not conform to seasonal migration or which we do not understand are termed by ornithologists, 'irregular migrations'. If it involves a movement of permanent residents from elsewhere, it is an 'invasion'. The young of many species on reaching maturity in late summer often wander for great distances. This is termed, 'juvenile wandering'. It is common in egrets, herons, gulls and other species. The most common cause for juvenile wandering is that they cannot compete with older birds for territory and food resources. They then have to wander until they find adequate food and habitat.
The case with the Northern Cardinals we are seeing here this fall appears to be an invasion, not juvenile wandering because the bulk of them seem to be adults and often in pairs. I well remember when we had no Cardinals here. The first ones moved in in the 1950s. Between 1952 and 1970 there were reports of 20 individuals in the province. After that reports gradually increased. The first nesting report was from Saint John in 1980. Those early reports are probably juvenile wanderings but the latest movement containing adults is an invasion, a very desirable one!
I had to go to Toronto to see my first Northern Cardinal in the early 1960s. Now many of us have them coming to our feeders and nesting in our yards and woodlots. Ontario once did not have any Cardinals either. The first record of one appearing in southern Ontario was in November, 1896. There were few reports there until 1910 after which numbers gradually increased. Southern Ontario had a marked incursion in the fall and winter of 1938-39. So mass movements of populations do occur in this species. There are reports of Cardinals sometimes gathering in large groups of more than 60 to 70 birds in sheltered habitats in winter.
As we all know, the Cardinal is a wonderful songster. His beautiful colour, his song and his pleasing behaviour around our yards make him a welcome addition. Let's look at his singing ability. Both genders sing, a trait which does not occur in every bird species. This bird sings a variety of gurgling and whistling songs. In fact, they sing more than 28 different songs. Some can be described as 'whoit cheer, whoit cheer, cheer, cheer, cheer' or 'birdy birdy birdy' or a metallic 'pik'. The songs of the male and female are indistinguishable. The female ceases to sing when she starts nesting.
Did you know that a courting pair sometimes sings in unison? I have not heard that. The males are ardent courters. They start by chasing the female from branch to branch. When he gets close to her he stretches out his neck and raises his crest. Both birds will sway their bodies from side to side and often sing together at that time. Sometimes the male will sing from a branch with his wings partly spread and drooping. If the female comes close he sings softly to her. Sometimes he will approach a female and land slightly above her. He extends his neck, raises his crest and slowly moves down towards her in a sliding motion. The female may then accept him or may move off to another branch where he comes and repeats the 'dance'.
Cardinals make good 'parents'. Both adults rear the young and 2 or more broods are raised. Three or four broods are raised in the south of their range. Young cardinals begin to sing at an early age. Their first songs are soft warblings. Cardinals prefer woodlands, scrublands, wetlands and gardens. We have plenty of habitat to accommodate the young. The increase in Cardinal population caused by this incursion is welcome and these birds should become permanent New Brunswick residents.
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