A NEW NON-NATIVE BIRD ARRIVING?

The spread of non-native birds is always problematic — at what point does a non-native species become "established" and thus become a "permanent" part of the local avifauna? From a State level, that is determined by the California Bird Records Committee (CBRC) based on their bylaws, which provide:

The Committee will also review records of breeding populations of introduced species not on the state list, but only if evidence is submitted that attempts to prove (a) the correct identification of the species and (b) the viability of the population. To be judged viable, a population must: (i) have bred in the state for fifteen (15) consecutive years, (ii) in general, be increasing or stabilized after an initial period of increase, (iii) be judged to have occupied all geographically contiguous suitable habitat to such a degree as to sustain the population and be thought unlikely to significantly diminish, and (iv) occupy an environment judged similar enough in ecological factors (e.g., climate, vegetation, food, shelter, competitors, predators) to the species’ natural habitat, or to other successful introductions, that permanent establishment seems likely.

The history of non-native introductions has shown four basic chronologies:

1. Escaped or released birds do not survive long (for example, many tropical species don't survive our winters) but those that are common in the pet trade do escape or are released, and are seen "in the wild": examples include various flamingos, non-migratory waterfowl, macaws, Budgerigar, Zebra Finch, and many more.
2. Escaped or released birds mostly don't survive long, except in a small area, where they breed and survive for years, but they never spread far from that small area: examples included Northern Cardinal in the Los Angeles area or Rose-ringed Parakeet in Bakersfield. On a national level these have included Blue-gray Tanager in Florida, Black Francolin in Louisiana, and Crested Myna in Vancouver, B.C. vicinity. Despite breeding for years, all these local populations eventually failed. The same applied to Red-crowned Parrot in MTY, which bred sporadically on the Monterey Peninsula from about 1983-2003, and got up to 13 birds, but all are gone now.
3. A more broadscale boom and then a bust with the entire population eventually disappearing. Spotted Dove in California was very common and widespread for decades, but now has declined to tiny remnants; they may be out-competed by Eurasian Collard-Dove. European Goldfinch in the northeastern U.S. had that trajectory — so common in the 1950-1960s that they were in the standard field guide, but no breeding population exists now.
4. A broadscale boom and expansion, often reaching a widespread peak (and sometimes a decline to a "stability" point, and becoming permanently established. Under the State bylaws, the CBRC has accepted 11 non-native species as meeting the criteria and thus "permanent establishment seems likely": Wild Turkey, Ring-necked Pheasant, Chukar, White-tailed Ptarmigan, Rock Pigeon, Spotted Dove, Eurasian Collared-Dove, Red-crowned Parrot, European Starling, House Sparrow, and Scaly-breasted Munia. Obviously, each of these species are "established" within their appropriate habitat — the Ptarmigan are only at high elevations above treeline in the Sierra Nevada; the Chukar is confined to very arid, rocky habitat in the interior; the Red-crowned Parrot and Scaly-breasted Munia are primarily in coastal southern California.

It is often impossible to determine which pathway a particular introduction of a non-native bird will take without years of data. In Monterey County only five species are currently considered permanent residents. All are widespread throughout the county: Turkey, Rock Pigeon, Collared-Dove, Starling, and House Sparrow. The most recent of these is Eurasian Collared-Dove. A small colony in King City in 1999-2000 was traced to releases from a local aviary. The first on the Monterey Peninsula was in March 2000 and the first pair was seen in 2002. More and more appeared each year and pairs were breeding. A large increase from 2005-2007 spread doves widely. Today they are common in populated areas throughout MTY. It took at least 5 years from the first one in Carmel in 2000 to determine that Eurasian Collared-Dove was a part of the MTY avifauna. [For birders using standard listing rules, non-natives are not "countable" until determined to be "established."]

We may now be in the early stages of the possible establishment of Scaly-breasted Munia in MTY. There are the CBRC-accepted populations in southern California from San Luis Obispo County to San Diego County (estimated at 1,400 birds in 2011) that continue to grow and spread. To the north, Santa Clara County has had escapees since 1997, nesting since about 2000, and more recently a potential population growing at specific sites (more details on Kendric Smith's web site). Recent reports at Pinto Lake in Santa Cruz County might suggest a spread southwards from the Santa Clara population.

The first 3 records from MTY were reported Nov 2017-Jan 2018 but then there were none for months; it seems apparent that these first released or escaped birds did not survive. This fall, however, there are 4 records around the Peninsula involving multiple birds in small flocks of up to 6-8 individuals. Laguna Grande Park and the Frog Pond Preserve had small flocks in reedbeds. These might be birds from an expanding population elsewhere in the State, but these sites are also the most logical spots for people to release non-natives. Non-native turtles and fish are known commonly from Laguna Grande and Roberts Lake; I personally talked to someone releasing their large pet goldfish because they had to move and felt these ponds would be places their pet might survive. Munias breed easily in captivity, and often breed in our autumn, so it is a logical time for pet-owners to release the whole family. So far, none of these groups has been seen in any week following a report, which might suggest the birds are not surviving. We just don't know the true facts, and don't have enough data to determine their status.

However, the presence of up to 15 individuals in small flocks at a feeder near Salmon Creek, just 2 miles north of the Monterey-San Luis Obispo border does suggest that it may represent an incursion into MTY of "established population" birds from the Morro Bay area. The location is less than 20 miles from "known" populations. Dan Richards documented these on 9, 21, and 22 Nov 2018 (photo right © Dan Richards, shows 9 munias at his feeder). These were not present every day but it does show that these munias were surviving for several weeks.

Because the Salmon Creek vicinity munias seem likely to have originated from "established" populations in SLO, they might be the first of a larger incursion from the south into MTY. It is possible that Monterey Peninsula birds are local releases or escapees, or perhaps longer-distance incursions from farther away, or a mix of both. To permit anyone to trace these movements, we are now approving these records in eBird. It will take a longer time to determine when and if a population of munias become established in MTY. They may happen . . . or it could be that they won't take hold here locally. Only time will tell.